Hello. It’s been a while.

A year or two ago you subscribed to this newsletter in the hope I’d be sending you regular missives about composting. And then the long-Covid I’d been struggling with kicked into a higher gear and I was incapacitated, both mentally and physically – no more composting, no more writing about composting, no more anything at all really. I wrote about it back in March on my personal site, if you’re curious.

The good news is that while I’m not in any way “better” I’m figuring out how to work with this new body and mind, learning how to pace myself and respect the limits to my capacities. And as part of that I’m giving the Aerobic Digest another go, writing a paragraph here and there when I have the energy, until a newsletter is ready to send.

My three heaps in August 2025 - l-r thermophilic, mesophilic and resting

Of course just because I wasn’t personally able to do any composting doesn’t mean composting didn’t get done. The rabbits still produce a giant sack of poop and pissy hay each week and it has to go somewhere. So every month or so I’d get a friend to fill up the hexagon while I sat and pointed like some wise old fool.

And then at Christmas my sister and brother-in-law arrived in Birmingham. To cut a very irrelevant story short, having lived on the other side of the planet in New Zealand for 20 years they ended up moving in around the corner from us. Lucy’s a keen gardener with an interest in permaculture, so she’s taken on what was threatening to become a rather neglected allotment plot, with spectacular results!

Every so often Lucy will send us a photo and we’re like, “is this our plot?”

Having someone actively working the plot means much more material to compost, and so we’re back to the three heap system, hot composting in the hexagon and then decanting to the right for mesophilic and again for final maturing. It was a bit slow during the drought but since the late summer storms hit last week it’s been cooking nicely. Which is good as there’s a lot more growing happening on the plot these days!

There’s something really nice about eating food that grew in the compost I made.

That’s enough about me. Here’s a bunch of things that caught my attention recently.

Compost Culture in Birmingham

Before I was properly disabled by my chronic fatigue I did a bit of freelance work for Compost Culture in Birmingham, designing and, while I was able, building their three-bay composting structures. But I never got to see them fully in operation so when they released a video about the project in February it was my first chance to see how they were being used and what was coming out of them. Quite an emotional feeling, I have to say.

I wanted to talk about this at the time but it was always evolving and it never seemed the right moment. Since then I’ve been slowly working on the build documentation and want to write a bit more about the why as much as the how, so look out for that in a future issue.

The 3D model I built last year.

In the meanwhile, enjoy the film, check out their website (look, there I am at the bottom of the page!) and get involved!

Can you power a website from a compost heap?

You might remember, way back in the last Aerobic Digest, I linked to an astronomy article that claimed our sun produces less energy than a compost heap. The number given is 276.5 watts per cubic metre, or about three 100 watt lightbulbs, which is nice to know. We’re all aware our heaps are giving off energy in the form of heat and capturing that otherwise wasted energy is something gardeners often ponder, be it for a seedlings hotbed or an off-grid shower.

So I was intrigued to stumble across Compost Computer, a project by the FutureEverything tech/art conference in Manchester, “an experimental project that will radically transform FutureEverything’s computational infrastructure by integrating more-than-human protocols”. A compost heap running a computer? That’s new.

Like most things that come from the intersection of art and technology you’ll probably be, at best, scratching your head and at worst screaming “what do you mean?” at the screen. I spent a while as a digital artist (I was on the FutureEverything website looking for talks from when I attended in the mid 2010s) and even I struggled to figure out what the hell is going on here. It’s a mini-masterclass in taking something interesting and smothering it in a find blend of academic jargon, art-speak and tech boosterism, but having dug a little deeper I can assure you there’s something interesting going on here.

This article goes into some actual detail of how it will work, and my reading is they’re not tapping the heat given out by the composting process. They’re utilising the chemical properties of the compost to build electric batteries.

An electric battery can very crudely be broken down into two different pieces of metal – the cathode and anode – which sit in a suitable chemical soup – the electrode. When connected to an electric circuit they react and generate a current. We commonly think of the electrode as “battery acid” – the gunk that you find when you leave an electric device in the drawer for years – but it can be a wide variety of media. An earth battery is literally metal rods plunged into damp soil, the chemistry of which can produce a current, and the earth itself conducts electricity, known as telluric current. Since soil is partially made of decomposing organic material it’s not a great leap to try doing to the same with a compost heap.

Testing small-scale compost batteries in the lab

I assume the end result of this project will be a full-size compost heap with a cathode and anode inserted and kept moist enough to ensure a current can be generated between them, with the hope that this is enough to power a computer running their website. (Which isn’t actually as much as you might think - see the solar powered website running Low Tech magazine.)

Of course composting isn’t a process that’s easy to control. You’re at the mercy of your available inputs, the climate and the available resources to manage the heap, and this could have some interesting effect on the battery.

More critically, if this process is taking energy from the heap, what does that do to the resulting compost? This project is working with MUD, a community growing project, and doesn’t want to inadvertently reduce their crop yields. They expect the electrochemical potential of the heap to be depleted before this affects nutrients, but it’ll be interesting to see testing of this. As we know, compost is not just about nutritional load. It’s about how that nutrition is locked in and slowly released, and how the microbiome interacts with it. That electrochemical stuff might turn out to be important.

Will it work? I’m cautiously optimistic. Compost heaps are huge piles of energy potential which we turn into heat and plant food. Why not also electricity? And if the heap is powering essential infrastructure that means there’s an incentive to look after and maintain it. I very much doubt we’ll be connecting our heaps to the national grid but as a proof of concept it’s certainly an interesting one.

Having understood broadly what’s going on here I find myself with more questions and thoughts and may well return to this project in a future newsletter. I’m particularly interested in how this might manifest as an artwork and what that artwork might be saying. If you have thoughts, please send them my way.

And yes, pop-culture heads, this is basically the same as how Doc Brown powers the DeLorean at the end of Back to the Future.

Criw Compostio in Machynlleth

Machynlleth is a town in central Wales which I jokingly call the home of the practical hippies. Up the hill is the Centre for Alternative Technology, established in the 1970s and acting as a gravity well for eco-minded folk. So it wasn’t a big surprise to learn they have a fairly impressive community composting scheme running in the town.

Like a lot of practical-focused enterprises the web presence for Criw Compostio is a little basic, with all efforts put into the composting itself, something made very clear in this great talk given by Ffin and Steph for the Social Food & Gardens online gathering.

What I really appreciated was the time given to making the composting setup fit the inputs available and the needs of the community, and how they use waste processing to, as they say, go “beyond community composting”. Next time we’re heading to the seaside from Birmingham I think a visit might be on the cards.

How to make a dead hedge

Add this to the list of things to do with woody material that won’t compost quickly. alongside Hügelkultur mounds and biochar. A dead hedge is probably better considered a temporary structure than a compost factory, although I guess you could harvest the remains once it’s done. Primarily though it’s a barrier constructed in a managed woodland, usually to mark out a path or protected area. The big advantage, as outlined in this lovely relaxing video, is how it’s made up of waste material, most of which would be hard to compost, creates a habitat for animals and fungi, and after a few years returns nutrients to the soil.

That’ll do for this issue. I don’t know when the next one will be out but if I had to guess I’d say in a couple of months? Maybe? I know I have plenty of things to write about so that’s not a problem.

If you have any questions about composting that I could answer in a future issue, please send them along. It's always good to have a writing prompt. And I'm always up for interesting links to share here.

Email to info@aerobicdigest.email or @ me on Mastodon or Bluesky where I keep tabs on the various #compost tags.

Your friend in rotting vegetable matter,

Pete Ashton
peteashton.com

Two full bays of compost maturing in the early summer.

Scroll to the bottom for a photo of Harold the Barrel.

Welcome to the thirteenth issue of my little newsletter all about the noble art of composting organic matter into soil food.

Later on I’ll link to some fascinating stuff I’ve found on the internet about composting and soil health, but first you must endure / enjoy my rambling journal from the allotment on how my heaps are doing and a curious piece of plastic I’ve found in them. Hold tight.

I’ve been sketching out some changes to my composting operation and today they started taking shape. It’s mostly just a move from one part of the allotment to another, but there are good reasons which hopefully will improve things.

Last summer I noticed the hexagonal heap was drying out on one side, despite it being designed not to dry out with a layer of sheep wool insulation. The problematic side faced south, getting the sun all day, and the south side of our allotment faces an open area of grass across which the southwesterly winds roar. My heaps are very exposed to the elements, which is not ideal.

Here’s a crude illustration I knocked up because I find making this sort of thing oddly calming.

A compost heap should be sheltered from the sun and wind. I might as well have put mine on top of a hill.

I’d contemplated building a large shading structure, or covering that side of the bay with reflective foil, and then I remembered we have a lilac tree on our allotment, and in its significant shade is an area we’re definitely not planning on using. So I drew a sketch.

H1 and H2 are the hot composting bays, which will also be hexagonal bays, so the H is doing double duty there. (Maybe they should be H21 and H22. Something to ponder.) On either side are shading panels, salvaged from an old shed, for morning and evening while the tree will protect from midday sun.

In front of H21 and H22 (yeah, I’m liking this) will be paving slabs for turning out and mixing, while at the back are bays for maturing compost, and to store buckets and bags of ingredients during the week.

Ultimately it’s not too different to the current setup, except I get to take everything I’ve learned over the last few years and do a bunch of stuff better, which will be pleasing indeed.

Over the last few weeks Val and I have been clearing the area (so many brambles...) and today I set up the first hot bay. It’s the old cube as I want to spend some time this summer refining the hexagonal design, but it takes up the same space so can be swapped out with ease.

Tomorrow I’ll fix that sun shade in properly and start filling it. H22 will join in July (give or take).

Odd pieces of plastic found in my compost

An occasional series.

As compost shrinks down, turns a nice dark brown and is spread over the beds for the worms to pull down into the soil, random bits of plastic that accidentally got into my waste stream make themselves known. Ideally they wouldn’t be there at all but it’s an inevitability at this stage of the Anthropocene and picking them out is just part of the process. Usually it’s mundane stuff like elastic bands that were bundling herbs, scraps of tape missed off boxes and a surprising number of spoons. But sometimes I get a real head-scratcher.

This is a perfect rectangle about 2mm thick and exactly 4cm x 3cm. The illustration is etched and has been inlayed with the compost. The back is completely smooth. While there are four circles in each corner there’s no sense of how it might be fixed to anything.

It appears to be instructions for turning something that goes in the front of a Volkswagen vehicle, maybe an attachment for towing, which needs to be firmly screwed in using leverage.

What had me puzzled for the multiples of minutes I was staring at it while forking over the heap is not what it means but why it even exists. Why is this the best way to communicate these instructions? Why is it better than, say, a sticker? What is the user of this device supposed to do with this small rectangle?

My best, if still tenuous, guess is VW produce identical cards for all their tools as part of a bespoke filing system, maybe a tiny rolodex, or a folder of plastic pockets. In which case I want to see more of them.

Anyway, that’s the odd plastic thing I found this month. Please feel free to send me photos of anything weird you come across in your heaps.

Another composting video

I’m enjoying making these videos of the compost management process. Mostly I like how the bugs and worms wiggling are really visible at high speed, zooming around as they try to get away from the light. Anyway, this is me emptying the resting heap into the maturing bay at 8x speed

Elsewhere on the internet...

Each issue I feature a handful of articles, videos and resources I’ve come across on the internet related to composting and soil health. I’m currently archiving the best of them here.

Sound recording follow-up

Last issue’s experiments in recording the soundscape of my compost heaps went down well, despite being not dissimilar to a badly tuned radio. Thanks for all the encouraging remarks! I posted the video to Mastodon before writing the newsletter, and just as I hit publish Broadfork sent me this fantastic Guardian article on this very subject:

Crunching worms, squeaking voles, drumming ants: how scientists are learning to eavesdrop on the sounds of soil

The big idea is to gather data about the subterranean biosphere without disturbing it, and identifying the acoustic signatures of different species gives farmers a relatively simple way to measure the biodiversity of their soil. It’s also giving some insights into how changes above, whether seasonal or human-caused, affect what’s happening down there.

The Guardian’s Soundscapes series, exploring "how our ears tell the story of ecological decline and recovery" ran through April.

How to make a decomposition timelapse

David Trood, aka the Weedy Gardener, shows us how to make timelapse movies of composting worms demolishing a banana in three weeks.

It does involve a reasonable amount of photography equipment and a dark studio (David was a professional photographer before he gave it all up in lockdown and became a gardener) but if you have all that and fancy a fun project, it’s actually fairly simple.

Reminds me of how mushroom timelapses are filmed.

The sun about as energetic as your compost heap

This is a story about how our sun is actually pretty inefficient. But what’s interesting is they use the energy generated by a compost heap as the yardstick, which I’d not seen before.

Good to know my heaps (which have a capacity of between 1.1 and 1.4 cubic metres) are generating around 300 watts, which is significant, but also not that much. Back to speculating how to capture and re-use it. via

The Four Pillars of Composting

The Wikipedia entry on composting has probably the most succinct yet comprehensive summary of the fundamentals of compost I’ve seen, and I’ve seen a lot of attempts since starting this newsletter.

Posting it here because for future reference, and because it’s as close to a work of art as we get in this game. Seriously, chapeau enlevé, Wikipendians.

Also, WONC. I'm thinking stickers, t-shirts maybe...

Meet Harold the Barrel

It was Compost Week in Australia recently and this chap made an appearance.

That’ll do for this issue. I’ve already started sketching out issue 14 so it might be sooner than later. Although I’ve probably jinxed that now. Within the month anyway.

If you have any questions about composting that I could answer in a future issue, please send them along. It's always good to have a writing prompt. And I'm always up for interesting links to share here.

Email to info@aerobicdigest.email or @ me on Mastodon or Bluesky where I keep tabs on the various #compost tags.

Your friend in rotting vegetable matter,

Pete Ashton

After a damp and cold spring my active heap finally went over 70 degrees this week. Hooray! The winter is finally over!

Some compost nerds warn against hitting high temperatures as it can burn out some nutrients, but I'm personally a fan of the super-hot heap, as long as you keep it moist. You can be sure you're killing off the weeds and diseases and it's a reassuring sign that you've got the mix right.

Plus this is only stage one. Once the thermophilic bacteria have exhausted their food and the temperatures get a little more reasonable there's plenty for the mesophilic dudes to do, not to mention the worms. I'd expect to see this sort of temperature for a couple of weeks after new inputs, or a full turn, and then it float between 30 and 50 degrees for a few months to really break things down. See below for a more scientific breakdown of the stages of composting.

Otherwise it's been steady as they go on the allotment with weekly topping up of the heap I started in the last issue, which might now be at capacity. If there's no significant reduction in height next week I'll cap it off and leave it until its full turnover in early June.

Speaking of turning, I made a video of my turning the currently resting heap. It was a long process so I've cut out some breaks and sped it up 20 times, and the battery ran out before the end, so it only runs for a couple of minutes.

This heap had been filled over three months, starting mid December with the final layer going in around mid March. The turn itself happened on April 10th, so the top material was pretty fresh. But from the middle to the bottom it was nice and dark and moist with loads of worms. And at high speed you can really see the bugs crawling around, desperate to get out of the light before the resident robins swoop in. This heap is alive.

I like to totally empty the bay onto the paving slabs in front and then re-fill it because it lets me see how things are going and then mix it all up properly. You'll hopefully see I'm spreading the heap around and as I fill it up again I'm aiming to put the really un-done material in the middle of the new heap. It's not a perfect process, but it works fairly well. It's been a month since this turn and I think it's probably ready to be turned again, this time into the neighbouring long-term resting bay.

The sound of composting

In 2013 I went on a guided walk around Edgbaston Reservoir run by SoundKitchen, a collective of sound artists, which I'm astonished to discover is still archived on their website a decade later. At strategic points in the walk we were invited to listen to field recordings made at that location with special equipment, revealing hidden worlds. One of them was a rotting log into which they'd placed some contact microphones which pick up tiny resonances in the wood. The result was an incredible recording of the nesting ants making a heck of a racket.

This has stuck with me ever since as something really special, like a microscope for the ears, but it only occurred to me this year that I could do the same with a compost heap. So I ordered some contact mics from ebay, plugged them into a recording device and plunged them into the heap.

The results are... sketchy? There was a lot of noise which I did my ignorant best to filter out (I am definitely not a sound artist), but there's definitely something there. Or not there, in one case. I put them in a video with photos of the heap I was recording.

The first recording is basically silent, which makes sense as it's the hot heap. Nothing bigger than a thermophilic microbe wants to be in here.

In the second recording you can really hear the worms moving around. Cool!

If I didn't know the third recording was of a drier heap with lots of wood-chewing insects I might assume it's the same as the worms, but it's not.

And the fourth one is the very much done pile. You can hear things moving but it's much less pronounced, like a faint echo.

On reflection I think I need to attach the mics to a wooden probe which the bugs will rub against to create a proper resonance. Just putting the mics in a plastic bag isn't really enough. But I do know that when the mics are held in mid air they're pretty much silent, so it's not just line noise.

More of this sort of thing to come I'm sure, and if you're local to me (Birmingham UK) and want to collaborate on doing something more advanced with recording the composting ecosystem, hit me up.

Oregon State University's composting resources

The OSU Extension Service is the community outreach department of Oregon State University and they mostly focus on improving health through food production. To this end they've put loads of gardening and farming resources online, and a decent amount of them are about composting and soil health. It's a mother-lode of rigorously sourced information tailored for the general audience. Just the sort of thing I like to feature here!

Start with Do The Rot Thing, a guide all the different composting systems and methods which is both comprehensive and concise, and comes with an even more concise PDF to print out.

Via

And then, golly, I don't know! There's so much good stuff and it all looks like deeply sensible, aimed at all levels of interest and ability. If you're plotting any kind of community composting programme you would do well to take what's been done here as inspiration.

Thermo-messo-whatnow?

Whenever I write about the bacteria in a hot composting heap I always have to check my terminology and while working on the opening section of this newsletter I came across this really good explainer of what's going on.

from Thermophilic bacteria and their thermozymes in composting processes: a review

It's an academic article, so gets pretty deep into the details, but don't let that put you off. The introduction is written in a very accessible way and it cleared up a few things I wasn't fully sure about. I think this bit is the best explainer I've seen of the stages of composting (edited for style):

Mesophilic II is the title of my next doom metal album.

Three songs about worms

• Youth Lagoon - Worms

• The Pogues - Worms

• The Tiger Lillies - Worms

That'll do for this issue. I think these are going to be monthly for a while so expect the next one around the start of June, though who knows, I might have more to share sooner!

If you have any questions about composting that I could answer in a future issue, please send them along. It's always good to have a writing prompt. And I'm always up for interesting links to share here.

Email to info@aerobicdigest.email or @ me on Mastodon or Bluesky where I keep tabs on the various #compost tags.

Your friend in rotting vegetable matter,

Pete Ashton

Gotta keep those heaps moist!

Through a confluence of circumstance I had a LOT of compostables stacked up and a nice empty bay to receive them today. One friend who also has rabbits had delivered seven bin liners of poop and hay, while another friend who also runs a micro-scale food waste collection didn’t have time to deal with the 10 buckets that arrived on her doorstep from a neighbour who’d spend the week batch-cooking for Ramadan. Add this to a few weeks of my own backlog, plus the mountainous results of my enthusiastically using my new cardboard shredder (more on that another day!) and I reckoned I could fill the whole thing in one go.

Knowing this might happen I jerry-rigged a way to suspend my phone above the heap and made a timelapse of the layering process, which I have annotated for your elucidation. Hope you enjoy it!

As a video it’s a bit of a technical mess and I could definitely do better, but I’m more interested in composting than documenting composting right now. I do quite like how it get closer and closer to the camera until you’re right in there and I am a bit curious to see how it would work on a giant screen… No, I’m no longer a lens-based artist. The heap is the artwork, not the documentation. And documentation for documentation’s sake is the enemy. This is as good as I’m going to allow it to get.

Anyway, a nice full bin. I expect it to settle quickly and I can add plenty more over April before letting it rest.

Fiona and I spent a bit of time pondering the development of the lower half of the allotment today. We originally had a half plot but took over the other half a couple of years ago. Here’s an annotated aerial photograph of our plot taken from an online map provider.

We’ve cleared most of the crap off new area since this photo was taken, and Fi had sowed a wildflower cover crop to get some nutrients in there, but despite doing everything by the book, the first attempt to grow crops was weirdly poor. The topsoil seems OK so we did an experimental dig and discovered loads of chunks of bricks!

Our allotment was established on land previously used as a brick factory and we’re quite used to finding redbrick gravel in the beds. But this spot must have never been cleared properly, or is part of the old building foundation. (The lovely lawn next to our plot is there purely because the topsoil quickly hits brick.) It’s no wonder the plants could only establish shallow roots.

We’re going to have to dig this whole area over and remove the bricks, probably down to a good half metre. Normally I’d be concerned about disturbing the soil structure, but there’s no structure to speak of and hardly any life. The soil smells of nothing, which is a bit odd when you realise it.

The end result will be a bed of loose soil with a lot of brick fragments and it’s going to need a decent amount of amending. And so, mes amis, we’re going to do some hügelkultur after all!

(Or maybe we’ll just dig in that pile of horse manure we got last year but haven’t figured out what to do with yet. Yeah. That makes much more sense.)

A tour of a worm farm

My hot composting process mostly produces mulch - rough compost that we spread on the beds which the worms then pull into the soil to finish off. I know very little about actual vermicomposting (to the point where for a while I thought it meant composting with vermin, however that might work) where you create composting structures specifically targeted at worms.

This video, made during a workshop at the Arizona Worm Farm, is therefore fascinating to me. It also has the bonus of being of somebody who has explained this stuff over and over and over and has it down pat. I particularly liked “browns are anything that was once a tree”. Boom.

I still think vermicomposting is a bit of an attention sink. One thing I like about composting in heaps is you can leave them for decent periods of time and they’ll be perfectly OK. With worms farms I get the sense you have to look after them in an animal husbandry kind of way, and I already do that with the rabbits.

Municipal composting advocacy

Composting Makes Sense. Why Don’t More Cities Do It? This is a great article on Modern Farmer which looks at some actual community- and city-scale composting schemes across the US and how they came about. Useful if you need to convince someone up the chain to fund your project! (via)

Modern Farmer looks like it has some great resources. I quickly came across this interview with a guy who wanted to set up a community composting scheme but faced outdated zoning laws prohibiting food waste processing, presumably because they put it in the same category as setting up a landfill site or sewage treatment works. Of course it’s totally possible to cleanly compost food waste in an urban location if you do it appropriately.

I wonder what the zoning laws are like in my city (Birmingham UK)? My chum Jez messaged me recently to say when his wife was managing Britain In Bloom for the suburb of Moseley a decade or so ago, she wanted to compost scraps from all the local restaurants, something I’ve been pondering for my area, but food waste was considered hazardous material and could not be handled within half a kilometre of any residential dwellings. Which is of course impossible in a city.

The great green wall of Africa

There’s a good chance you’ve already heard about this – it’s been all over my internet at least. The Sahara desert is spreading south at an alarming rate and the Great Green Wall is a massive project to stop it. How do you stop a desert? With thousands of small round beds designed to hold moisture and plants to build soil structure.

I will admit to being incredibly cynical about this when I first heard about it as it seems far too good to be true – like those greenwashing “plant a shittonne of trees to save the planet” things – but the project looks solid and from what I can tell it’s working. Amazing stuff!

Tips to speed up composting

It’s worth preceding this with a reassurance that slow composting is perfectly fine. In fact it’s probably the best sort of composting because it’s the most natural and allows the micro-organisms to work at their own pace. In nature, plants die and fall to the ground and it takes a while for the soil biome to process them into food.

The main reason people like me might want to speed up our compost process is because we tend to be processing a lot of material in a smaller space and want to get it done before we get more material delivered. If that’s not you then don’t worry, it’ll be done when it’s done.

Like most articles written to get traffic from Google, How To Speed Up Composting (10 Tips For Faster Results) takes the long route to communicate some fairly simple things, but it does have this great diagram, which I’m totally in love with.

It’s so out of place that I assumed it was nicked from elsewhere, maybe some awesome composting comic, but there’s nothing on TinEye. As you’ll know I’m a big fan of the perforated drainpipe so it’s lovely to see it.

Bristol Living Soil

“We want to regenerate Bristol’s soils, rebuild community and share knowledge” says Lara Luna Bartley of the Bristol Living Soil community compost collective who have a great logo.

Their business model is based on a subscription of minimum £10 a month in return for which you get an annual delivery of high quality compost. It looks like they’re using those big octagonal tumblers and say they have capacity to process “food waste from 20-30 households and 5-8 businesses on our current site.” So not quite community-scale but not nothing either. Although from a sustainability point of view that’s not going to generate enough income to pay anyone a decent wage to manage the scheme.

I’d be interested to see how much they produce in a year. If I had those inputs I might get 3000 litres of compost? Maybe more? So based on a totally arbitrary reckon, each person would get about 100 litres of compost for £120. Standard compost from our local garden centre is £4 for 10 litres, so it’s probably not competitive with that, but it’s also probably not the point - this is aimed at people who want to do something to make a difference and the compost is a bonus. Plus unlike Birmingham, Bristol actually has council food waste collections.

More interesting is the commercial angle. At my bakery we pay Biffa £90 (inc VAT) a month for weekly collections of a 240 litre wheelie bin. If this was being collected and processed locally for roughly the same amount we’d certainly be interested.

Anyway, I’m picking at the details because I’m really intrigued how something like this could be expanded to 200-300 homes and 50-80 businesses. Regardless, it’s fantastic to see this happening in Bristol. Next time I find myself visiting the land of (some of) my youth I’ll try to arrange a visit.

That’ll do for this issue. The next issue will be out the next time I do some composting!

Please continue to send compost-related things to info@aerobicdigest.email or @ me on Mastodon where I keep tabs on the #compost tag.

Your friend in rotting vegetable matter,

Pete Ashton

I don’t know if red wigglers is the official name for them but that’s what Sean at Edible Acres calls them in his videos. They’re the thin red worms that multiply like crazy in your compost under certain conditions. Are they baby earthworms? A whole different species? I don’t know! One day I’ll look them up.

For some reason I haven’t seen consistent worm action throughout my heaps since I scaled up from a plastic Dalek, but today I hit the jackpot. Thousands of the little red dudes!

This is the “stinky heap” in the hexagonal bay that I turned in on itself in January. It had gone anaerobic because I’d gotten the balance very wrong when I filled it in October – far too much food waste and fresh greens and not enough dry browns. During the turn I’d added copious amounts of shredded paper and it really made a difference. From a foul-smelling gloopy mess to a sweet-smelling worm party in under two months.

This is now cooked and needs to rest at a cooler temperature while the worms and other critters process it further, so I turned it into the middle resting bay to free up the hexagon for the next batch. As I did so I was visited by not one but two robins. Sadly the second one flew off as I lifted my phone for a photo.

Earlier in the week our new allotment helper Val was back and we emptied the middle resting pile into the “done” bay. This contained two very distinct batches - the bottom half was a normal-ish mix of veg, hay and cardboard from the hexagon which I’d turned in there in October - nice compost but not very crumbly. The top was from the square bay which had taken 20+ sacks of leaves and chipped branches from my brother in law’s hedge. While I did layer it with food scraps and shredded paper it was still pretty wood-heavy, which really stopped it clumping.

I think they’re both perfectly good batches of compost but they sit at either end of the acceptable scale. Now they’re mixed up in the ‘done’ bay they’re hopefully nice and goldilocks.

via

A short introduction to biochar

One of my medium-term goals is to figure out how to make biochar – charcoal for use as a soil amendment – in a suburban setting. To turn wood into charcoal you need heat. This is usually achieved by either half-burning the wood and stopping before it becomes ash, or placing the wood in an airtight container and surrounding it with a fire. (The resources I’ll post below will explain this in more detail.)

The problem is you need fire, and allotments in Birmingham do not allow bonfires except in November and only for organic waste generated on site, mostly because people live close by and would like to leave their washing out, which is fair. Of course it’s possible to create a high enough temperature to pyrolyse wood in an electric or gas oven – at my bakery we once found a baguette that had gone through the whole bake shift lost at the back of the oven and had totally carbonised – but loading a food oven up with random bits of wood is a total no-no. It would need to be a dedicated tool, not to mention the financial and ecological running costs.

My friend Gerry is looking to make charcoal pencils from thin branches of coppiced willow and will probably do this by putting them in a biscuit tin in a small bonfire. Unfortunately I would want to produce a big enough pile, like a few hundred litres, to make a difference to my compost over a year. So until I can find a nearby location where I can make a lot of smoke, the biochar idea is on the back burner (sorry-not-sorry).

So what exactly is biochar, why do we need it and how do we make it?

Probably the best explainer I’ve seen is what first put it on my radar - Bruce Darrell’s video from his RED Gardens project. In eight minutes he introduces the concept, the history and the various methods, before showing how he makes it using a simple pit dug in the ground.

The big lesson, and one which I keep forgetting, is that biochar is charcoal PLUS biological matter. Charcoal is incredibly porous, like a sponge, and acts as storage and slow release of nutrients, as well as a home for microbes. But if you add it “raw” to the soil it will just soak up any goodness that is already there.

If you prefer your information in textual form, the last thing I read, and what prompted me to write about it this issue, is the biochar explainer on the MIT climate portal. While Bruce is looking at it as a practical amendment, this is seeing it more in terms of carbon sequestration, which it is good for too.

For more of a deep dive, I’d recommend Porterhouse and Teal’s playlist of videos which I learned a lot from. His introduction is on a par with Bruce Darrell’s but instead of using a pit he uses a retort, a sealed barrel of biomatter within a large barrel of fire - essentially an oven. Also, look out for the video of making charcoal from animal bones - useful if your food waste stream comes from carnivorous households!

An attempt at explaining the science

Before I got into this I had no real idea what charcoal was. I just assumed it was like normal coal, only crumblier. The science of pyrolysis turns out to be very simple and kinda fascinating.

We all know that burning organic matter produces carbon dioxide, because organic matter contains a lot of carbon and fire needs oxygen. Put the two together and you get CO2. But of course there’s more to organic matter than carbon, summarised as CHNOPS, or carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Crudely speaking (and I’m sure an actual scientist will correct me) the smoke you get from a fire comes from the non-carbon elements, which is why charcoal is sold as a ‘smokeless’ fuel, and wood-burning stoves should only use dry wood.

During pyrolysis, we heat up the wood to the sort of temperature where it would normally catch fire, but restrict the amount of oxygen available to it. If there’s no oxygen then the carbon cannot turn into CO2, but other elements which do not need oxygen will be forced out by the high temperature. The end result is pure carbon.

Of course these non-carbon elements have a value to the garden. One reason we compost is to capture and process them into plant food. But it’s not easy to get them out of lumps of wood, and the benefits of having that massive surface area (2,000 sq metres within one gramme!) are huge.

Next steps

I’ve been collecting wood that’s not suitable for composting for a couple of years and the first thing I need to do is decide whether I want bury it in a hugelkultur mound or make it into biochar. Both have their appeals, which is annoying.

If I do go the charcoal route, I need to dry my wood stock over the summer, which means constructing a simple weatherproof store, so that’s a job for the spring.

Then I need to remember to make it in November when fires are permitted on the allotment. I’ll probably go with the cone pit rather than invest in a retort at this stage and since it takes a few hours maybe make a social event out of it. (I used to have lots of bonfires when I was younger and miss them.)

If you have any experience in making biochar and have tips, please let me know. And if you’re in Birmingham (UK) and would like to collaborate on something like this, hit me up!

Thanks for reading!

Please continue to send compost-related things to info@aerobicdigest.email or @ me on Mastodon where I keep tabs on the #compost tag.

Your friend in rotting vegetable matter,

Pete Ashton

Today I was joined on the plot by my friend Valentina. Val needed to get out of the office, and I needed someone to help me shift a shittonne of compost from one place to another. Win-win!

I’m still on rest and recuperation - I wrote about my burnout in more detail on my non-compost blogletter - and all four of my heaps are now full. I urgently needed to empty the fourth storage bay onto Fiona’s beds to free up the third resting bay so it can take the contents of the second while the first rests. I equipped Val with a pitchfork and wheelbarrow and she got to work for an hour, leaving me to swoop in and finish it off.

This was the batch I wrote about in October, started when I had Long Covid and capped off when my parents died. As such it’s one of my worst attempts at composting, but I can forgive myself.

The final results were not too terrible. Lots of matted newspaper, which was annoying to remove, but otherwise a pretty decent mulch. We were able to cover five beds with a decent thickness ready for spring planting. Nice.

The compost itself was the right level of damp and crumbly. A few lumps but nothing the worms won’t sort out.

We filled a tub with matted and uncomposted newspaper which I didn’t want to put on the beds. It’s still good carbon so I’ll tear it up and add it to the next active bay. But other than this and a few small clumps of hay, everything else had broken down.

Action shot!

Five-and-a-bit beds covered in nutritious mulch. Now it’s over the to the worms and other macro-organisms to pull it into the soil. (We also topped up the paths with some rather dark wood chip - those strips marked by the bricks are not compost!)

Now I have an empty bay and the next time Val is free we can do the decanting of 2 to 3 and 3 to 4 and get to work filling up 2 again. It never ends!

I’ve collected a LOT of compost-related links over the last couple of months and I’m going to dump some of them here with a bit less commentary than usual. You can find all my composting bookmarks on this page.

Soil Food Web videos

I’ve been really impressed with the last two videos Dr. Elaine’s Soil Food Web have included in their email newsletter. They’re the clearest explainers of what’s actually going on when add compost to a no-dig bed that I’ve ever seen and I commend them to the community.

Nutrient Cycling looks at what and how plants take from the soil, while Formation of Structure is a deep dive (deep dig?) into how to renew compacted or damaged soil. I sent the second one to my sister who had asked me to explain what soil actually was and it really helped her to get it.

A terrible compost quiz

Amusingly I got Dr Elaine’s newsletter after doing their online quiz, which got our Birmingham composting WhatsApp group in quite a tizz because it, frankly, not very good at all! Take this question:

I hope you’d agree that B is the correct answer. After an initial burst in the 60s to kill any seeds and diseases, I’d be happy if my piles stayed around 50 degrees for a couple of months as they do their thing. But this is the “correct” answer.

Which, as I hope you’ll notice, was not one of the options given, and is also nonsense. You need oxygen to get heat - a compost heap above ambient temperature cannot be anaerobic, surely? (Do let me know if I’m mistaken.)

Community composting in the news

Hartcliffe resident recycles community food waste for compost scheme (BBC). Not much detail but it looks like it’s funded by a local charity and is using a Ridan composter.

Marldon community launches its own composting group (BBC). Again, scant information, but this one looks like it’s in collaboration with the council’s parks staff.

Six inches of soil - a documentary feature film

Six inches of soil is a documentary about regenerative farming in the UK. While I’m very interested in this subject, there’s something about the trailer that rubs me the wrong way (earnest middle class people blaming consumers perhaps…) so I’m reserving judgement until I see it.

Assessing soil health using a microscope

I know I’ll be doing in this a few years time, and it looks great fun.

Idaho lawmaker says human composting could lead to cannibalism

Nonsense, of course, and highlights a fascinating anthro-centric ignorance about how organic matter decays.

Illustration of the anatomy and structure of an earthworm

It turns out earthworms have five hearts. ❤️❤️❤️❤️❤️

via

Optimizing food waste composting

Tim O’Neill and Ryan Costello’s study looks at an issue I hadn’t considered: composting facilities that have traditionally processed materials from parks and gardens are now being asked to deal with household and commercial food waste. This is a very different proposition with a much lower pH and needs to be treated differently. via

A short hugelkultur video

I continue to be interested in hugelkultur, from the use of wood that won’t easily compost to the water-retention properties, but there’s a lot out there. This is probably the best short introduction I’ve found.

That’ll do for now!

Please continue to send compost-related things to info@aerobicdigest.email or @ me on Mastodon where I keep tabs on the #compost tag.

Your friend in rotting vegetable matter,

Pete Ashton

Hello you.

My first trip to the heaps in 2024 and there was a lot to do. Not only did I need to load up the current bay with a month’s worth of veg but the hexagonal bay was well overdue a turn, and I knew it was going to be a bad one.

According to my notes this was mostly filled in October when Fiona was clearing the allotment plots and giving me a lot of plants. Also the rabbit’s hay was particularly green without the usual long stems. It was effectively grass cuttings, which is fine but needs padding out with browns. Usually this would be paper and woodchip, but the woodchip pile was mostly leaves with very little woody material. I did my best with what paper I could get but by the end I was sure the mix wasn’t right.

And so it proved to be. I forked out very heavy clumps of barely rotting food, stringy plants, all with a quite pungent smell. Aerobic digestion this was certainly not!

I’d come prepared though and layered it back in with copious shredded paper, mulched Christmas trees and actual woodchip. This should get the temperature back up and speed things up, fingers crossed.

The Pete compost method, 2023 version

I was looking back at my notes from last year and noticed I have a method now. It’s not perfect by any means and I’m always looking to tweak it, but this is how I aimed to process a compost heap in 2023, using a three bay system where the two outer bays are primary and the middle one is secondary.

Adding material

• Start with a layer of woodchip that will allow air to pass along the base of the heap. Include a few perforated drain pipes buried in the woodchip.

• Layer ingredients as follows:

  • Food scraps and/or plant material

  • Shredded paper and cardboard

  • Spoiled hay and poop from the rabbits.

  • Woodchip

• Top off with a decent layer of woodchip to retain moisture and prevent smells.

• Depending on the dampness of the ingredients, add roughly 5 litres of water / urine for each of the above layer cycles. Alternatively soak the paper and hay before adding.

First resting

• Once the heap is full, leave it for a few weeks. A month is probably long enough. Water during hot weather.

• Turn the heap out into a pile outside your bay. See how it’s getting on:

  • Claggy lumps of food and bad smells mean not enough brown. Needs more woodchip and/or paper.

  • Dried out means not enough water. This is a problem in the summer - add plenty of water and potentially keep it covered to reduce evaporation.

• Shovel it back into the bay, adding browns and/or water as appropriate as you go.

• Top off with a decent layer of woodchip to keep in moisture and reduce smells.

• Leave it for another month or so.

Second resting

• The heap should now have shrunk to half the size of the bay.

• Shovel the heap into your middle secondary bay. If it’s empty it will be half full. If it’s half full this will bring it to the top.

• If your fixes from the previous turn haven’t helped (or have gone too far the other way) add water and/or browns as needed.

• Water the heap and layer some cardboard or paper sacks on the top to keep moisture in.

• Once you have a full bay, leave it for another month or two, watering occasionally if the weather is warm.

Done?

• Dig into the heap with a fork or giant corkscrew and see how it’s doing. Check mostly for smell - anything undigested will have a stink to it. If it smells nice and earthy then it’s good to go

• Not everything will have rotted. There’s likely to be plenty of larger chips of wood and plants stems, but these are OK. If you find any lumps or pockets that definitely aren’t done, throw them into your active pile.

• Either turn this into your storage heap or spread it directly onto your beds. Be aware that it will still be quite raw so maybe avoid spreading around delicate plants, but it’s perfect for beds that are resting over the winter.

That’s a minimum four month turnaround which is doable, though I tend to stretch it out to eight or nine depending on how much material I’m getting. Bear in mind I’m just using this for spreading on the top of no-dig beds. This isn’t “finished” compost for potting or anything like that - it’s more a mulch. If you want a nice fine compost then I’d suggest taking my end product and giving it to a worm farm. But that’s a whole other topic.

Historical document corner

Thanks to Liz Howlett for sending through this scan of an eight page guide to composting from 1939 by the subject of her newsletter, Adela Marion Curtis.

It’s a fantastic mix of the sensible advice and opinionated rants. I learned a few useful things, the key one being to water the sides, not the centre, of the heap. I usually water evenly, but of course the sides will dry out first. I’m definitely going to do this going forward.

But then suddenly we’re into a tirade against rats:

And an epic rant about the evils of municipal sewage.

The “foolish godson” is probably John Harrington who invented the flush toilet in 1596.

Marvellous stuff. Download the PDF here.

Art / science : Listening to soil

Via this overview of biodiversity issues in 2024 comes the notion of monitoring the health of soil by the sounds it makes.

The link is to an academic paper which feels like a first step in taking the sounds of the creepy crawlies that vibrate their way through the soil and interpreting them. It also raises the intriguing idea of noise pollution affecting soil health, just as it does to marine life.

I have no idea how useful this is, but anything that encourages us to see soil as a complex arena bursting with life is of interest to me.

Karine Bonneval via https://www.karinebonneval.com/eng/projets/ecouter-la-terre-10

The paper has an intriguing image in it from Listen to the soil, an artwork by Karine Bonneval whose work deals with “breathing, moving and listening with the plant world”. She created these terracotta listening devices inspired by microscopic fungal structures which the visitor holds their ear to, imagining they’re listening directly to the soil itself.

The gallery exhibit is cool but I’d love to come across one of these in the woods.

Karine Bonneval via https://www.karinebonneval.com/eng/projets/ecouter-la-terre-10

I have a load more links to articles and videos saved in my big document of things to write about in this newsletter but I’m going to save them for next time, which hopefully will be soon. Or maybe it won’t! Who knows.

Please continue to send compost-related things to info@aerobicdigest.email or @ me on Mastodon where I keep tabs on the #compost tag.

Your friend in rotting vegetable matter,

Pete Ashton

Feeling my age as I turn the second-oldest into the third-oldest.

Today was my first visit to my compost bays since November 5th, and also my first newsletter since that evening. I said when signing off that I wasn’t expecting to write for a couple of weeks but didn’t expect it to last quite so long.

I’ve been knocked back by exhaustion this last month. A combination of a very weird year, the ever-lingering Long COVID and that nasty November cold that was going around all conspired to wipe me out, putting me on light duties at work and forcing composting on the back burner. But today Fiona helped with some shovelling and I got back on top of it again.

The first order of business was to free up a bay to start a new heap, so we turned the the second oldest pile into the third oldest. They both look great – nice and dark and loose – and should be ready for spreading very soon. Both had a lot of woodchip added at the time and confirm my theory that while it may not break down quickly, woodchip helps everything else rot, possibly by giving the microbes somewhere to hang out and by aiding the airflow.

Seven month old compost, having rested in the cool for two months. The worms are loving it.

With the square bay free we got to work filling it up. I had six weeks worth of hay from the rabbits but I don’t like to let this dominate the pile. While it sits in that nice spot between green and brown, it has a tendency to get too dry or too wet on its own and needs to be part of a mix to break down properly.

Unfortunately I haven’t been hoarding that much food waste this last six weeks (or maybe that should be fortunately, given it sits outside the back door in stinky buckets) but I did take delivery of all that horse shit in the autumn! Balance that out with a decent helping of shredded paper and woodchip and hopefully we have a good mix.

Over the next fortnight I’ll be attacking the hexagonal bay which I decided was done in November and which has been patiently sitting in the autumn rains, waiting for its first turn. This will involve adding a lot of paper and woodchip as I fear I went too heavy on the greens. If it’s not a stinky anaerobic mess in there I’ll be amazed.

Fun things to read and watch.

I’ve started the process of archiving links in a more useful way on Raindrop, a bookmarking service I’ve recently been playing with. So far I can share this dump of everything but I hope to make it into a more useful service as I get used to it. There’s a lot of useful stuff on the internet and I have this eternal urge to organise it all.

If you’re taking some time for yourself this winter break I hope some of these will prove an interesting diversion.

Thermal imaging a compost pile

I have a small thermal camera from when I was a lens-based digital artist years ago (I’m much better now) and it’s never occurred to me to dig it out and point it at the compost. Having seen this video from Edible Acres I’m definitely going to give it a go now.

Caring for “the below-ground livestock”

I love this term for the organisms that live in the soil, from bacteria to fungi to worms and bugs. It comes from Soil, Diversity and Resilience, an article on the Landworkers Alliance website by agrobiodiversity farmer Tim Williams, giving a succinct introduction to the benefits of moving away from a monoculture farming systems.

A no-dig orange peel forest

In the 1990s a couple of researchers convinced an orange juice company to donate some land they owned near a national park and in return they could dump all their waste orange peels over a three hectare patch of barn soil-degraded land. 1,000 truckloads later it looked like this.

Which obviously doesn’t look great, and for various reasons the project was abandoned. But when the researchers went back 16 years later they found a thriving forest with a massively increased biomass, compared with a control patch of land that hadn’t been covered in orange peel.

The best theory as to what happened is the oranges were so dense they suppressed the invasive grasses that were the only thing able to grow in the degraded soil, and then once to peel had rotted to mulch, native seeds could blow in and take root. In other words, no-dig forestry!

More here / via

Grass clipping to sheep guts

I love the wild journey in this otherwise light look at a New Zealand woman’s composting adventures. She starts off as all of us might, composting her lawn clippings and struggling to get the green / brown / water balance right, but soon she’s adding sawdust from her brother’s firewood business, fish heads from her fishmonger friends, and before you know it, “when we kill a sheep we’ll throw the guts in”.

via my sister

A healthy soils and compost policy guide

This is a bit heavy for me at the moment, but if you’re into policy documents and webinars you may enjoy this deep dive into what looks like a concerted effort from the Institute for Local Self-Reliance to sort out the woeful state of the USA’s soil: Healthy Soils and Compost Policy Guide: Synergies and Opportunities

A nation that rebuilds its soils rebuilds itself

Enjoy this great lecture from Professor Karen Johnson which wonderfully outlines the importance of thinking about soil, riffing off Roosevelt’s quote, "a nation that destroys its soils destroys itself” referring to the American Midwest dustbowl of the 1930s depression. This is the sort of thing that gets me enthused about composting projects, because it’s not just about food waste or even about growing food - it’s a metaphor for how we live.

via Laura at TAWS

What food waste means for climate change

Some scary statistics around food waste and what happens to it (so much is landfilled where it generates methane) plus this neat chart. Improving the top ones is going to take some radical societal change but increasing compost capture (if you like) doesn’t feel too hard.

Winter composting with Charles Dowding

Just as I’ve getting ready to put this issue to bed I spot a new Charles Dowding video in my feed, and it’s one of his composting ones!

He’s been running a few experiments in his garden over the years from his I-want-one seven bay structure to a more DIY pallet-based 3-bay system, plus a couple of Daleks and a wormery, and it’s great to see how they work to produce different types of compost at different times of year.

Nice tip for spreading compost in the winter so the frost breaks it up. I hadn’t thought of that.

Composting gift guide

It’s far too late to order anything for Christmas and I wasn’t seriously going to do a gift guide, but I did come across Brenna Quinlan, an illustrator and permaculture from Australia who does compost-related prints and t-shirts. I like this spin on the Rousseau quote.

And then there’s the mug my mum got me last year.

That should be enough to keep you going! See you in the new year, if not before.

Your friend in rotting vegetable matter,

Pete Ashton

Hello compost dorks.

It’s definitely autumn. My heaps are barely scraping 60 degrees and there are leaves just everywhere, just lying around on the ground waiting to be swept up and added to compost piles across the land. (Or left where they are to mulch their parent trees, as nature intended.)

It’s also been raining a lot here in Blighty and my heap with the deliberately leaky lid is extra moist right now, creating the perfect conditions for a delightful dusting of snow-like fungus.

While I only started it a month ago, this particular heap is probably full now and will rest for a few weeks before I turn it. When I do I’ll be adding a load of brown (cardboard, wood chip) as it’s far too green at the moment. A surfeit of food waste and very grassy rabbit hay (cut far too early really, but this summer has been problematic for hay farmers), plus the post-harvest plants from the allotment. You can tell it’s on the verge of getting anaerobic and about to get stinky, but it’s perfectly salvageable and I have high hopes.

Food shredder search continues

After posting the screenshot of the food shredder last issue I directly asked the #compostodon tag on Mastodon and was told I might be looking for an apple scratter, used to pulp apples and release their juice. The principle is right, but I'm not sure how effective it would be with less pulpy foodstuffs. I might be able to borrow one so look out for that adventure. In the meanwhile I’m still looking for something that looks like this:

I currently use this mulcher from Forest Master which is OK but really designed for mulching long thin branches of wood. A bucket of sludgy food tends to need forcing through and has a tendency to clog the exit, meaning I have to sort food waste by hand so only the really solid stuff goes through it. This is fine at my current levels, but if I want to take more food waste it will quickly get annoying, hence the search.

New fungus feature film alert

For the last few years the go-to documentary about what we might call Nu Mycology, or the Fungal Revival, has been 2019’s Fantastic Fungi with it’s focus on the pioneering work of Paul Stamets. It’s a great film which I highly recommend. (Looks like it’s on Netflix right now).

But it seems we have a challenger! Fungi: Web of Life is out in IMAX cinemas over the next few months, narrated by Björk and presented by Merlin Sheldrake, presumably reciting the key points from his book as he searches for a rare blue mushroom in Tasmania.

We’ll have to wait and see if it lives up to the promises of the trailer, but it’s bound to give us plenty of gorgeous time-lapse photography of mushrooms blooming. If you’ve ever wondered how these are filmed, Wired did a nice interview with Louie Schwartzberg whose work appeared in Fantastic Fungi. It turns out it’s all done in a studio.

How-to guide from a Brussels Kitchen

I like reading really simple how-to guides for inspiration as explaining something in basic terms is hard, and when you see it done well it’s delightful.

This guide, from the website of a small kitchen garden in Brussels, gets right to the point, explaining in two short paragraphs the importance of soil and the role of making compost to feed it. It also has some great photos that work really well as thumbnails - no mean feat when most of your subject matter is a shade of muddy brown.

via kitchen-garden.be

Theirs is not a medium or large-scale operation and this guide is aimed at those building one heap per year, which to be fair is most people, so I’m doubly grateful for that. Most of the compost nerds I know, self included, are always looking to scale up, yet we’re the ones people come to for advice. One to keep bookmarked.

Serving up Science on soil health

Sheril Kirshenbaum from PBS’s food channel does a fascinating experiment in this video about the relationship between soil health and the food grown in it.

At 3:24 she takes two clumps of soil from the same farm. One is from a no-dig bed which has retained its structure. The second is from a frequently ploughed field and has less structure. She pours water through these and the results are quite shocking. I was expecting the water to pass through the second clump but not to dissolve it, while the first was barely touched.

Scale this up to the farmed environment and you can see why we’re facing a soil crisis. It’s not just that the earth isn’t holding nutrients - it’s that it’s literally being washed away, and all the chemical fertiliser in the world won’t help you if there’s nothing to fertilise.

I was thinking about this as I watched my local river turn a vibrant brown after the recent storms. It doesn’t pass through much farmland anymore (Birmingham happened to those a century ago) but it’s clear what soil remains in its watershed is not holding itself together.

For more on soil health I highly recommend the book A World Without Soil by Jo Handelsman which was one of the main things to turn me on to its importance. It’s a very readable book by someone who found themselves working for the Obama administration where she discovered the emerging crisis in the nation’s soil.

Hans Walty’s mushroom watercolours

Jason Kottke found a trove of watercolour paintings of mushrooms by amateur mycologist Hans Walty made from 1913 to 1944. You might assume he selected the best for his post, but a look at the full collection on Wikimedia shows he barely scratched the surface. These are all stunning.

#compostodon highlights

• Bringing the worms into the living room.

• My compost brings all the robins to the heap.

• A handy thermometer scale.

That’ll do for this Aerobic Digest. Six issues and two month in and I think I’m sort of getting a feel for this thing. While feedback has been random and slight it’s been positive, which is nice, and while subscribers have settled in the mid 60s that’s still a nice number of people to visualise. I was bit worried I’d run out of things to talk about once I’d exhausted my bookmarks but it seems to be going ok? Well enough to carry on for a bit longer anyway.

I’m reluctant to say what’ll be in the next issue since I’ve spectacularly failed to talk about hugelculture and horse manure, both of which were trailed at this point of previous missives, but I am starting a build for a community composting scheme which will go up soon, so maybe I’ll document the thinking behind that. Or maybe I won’t!

Lots happening in the real world so I expect I’ll next write towards the end of the month.

Your friend in rotting vegetable matter,

Pete Ashton

Let’s dive right in with a question from m’learned chum Jez:

First and foremost, having rats in your compost is not a problem for your compost. They won’t harm the process and if anything help it along by burrowing in and aerating the pile. But there are reasons you might not want to find a rat in your heap.

The biggest one is really public relations – there’s an assumption that compost heaps attract and encourage rats and mice. While it’s debatable whether they do much to increase the general population, especially in an urban environment, a warm compost pile can be a great home for them.

As prey animals rats and mice are shy and keep themselves hidden from humans, which means humans are often under the delusion that there aren’t that many around. Since turning compost will be one of the few times we come face to face with rats, its easy to come to the mistaken conclusion that the rats are only there because of the compost.

Faced with this faulty logic, those of us that are interested in community composting very quickly realise that the best way to avoid these conversations is to rat-proof our heaps. I’ve been using a 6x6mm wire mesh which is not that cheap but does the job. This way even if there’s a massive local rat population we can confidently say it’s not our doing.

Weil's disease from rat urine is often cited as a risk, but only if you’re working your heap without adequate protection and there’s a lot of standing water around. If we’re being honest composting can be health hazard if not done with care, whether your breathing in dust when turning a dry heap or not wearing gloves when handing mouldy food. I’d probably put rat piss low on the risk register but eliminating any chance of it does help with the the above public relations.

Probably the main reason for me to rat proof my own heaps is that they’ve been much tidier ever since. Tunnels dug and holes chewed can make a big mess which muggins here has to tidy up and repair. Covering everything in a fine mesh means that I find my heaps as I left them, with the added bonus of no cute little shocks and surprises as I dig.

Bruce Darrell has a characteristically comprehensive video about his nine methods for controlling the rat population at RED Gardens. It’s bit a gruesome at times, so not for the squeamish, and his preferred solution of asphyxiating them with a propane flame thrower might not scale to your setup, but along the way he answers a lot of questions about why this is necessary for him (they eat his crops) and how to be relatively humane about it.

Photography: Mushrooms in Moseley Bog

It’s mushroom season here in the UK and Fiona went on local mycelium legend Lucas Large’s tour of Moseley Bog last weekend. Here’s a couple of her photos from the walk

I wasn’t able to go but last year I had a great time and took loads of photos. You can see my full album here while Fiona’s are on the Walkspace Instagram. I remember I took my chunky Nikon DSLR with a decent lens but my phone was much more effective. It let me get right into the undergrowth and down to a fungus-eye view, and tap-dragging to darken the image made everything pop beautifully.

If you’re in South Birmingham, Lucas is doing a similar walk around Highbury Park this Friday 27th. I may well be there!

Video: The bEartha community composting machine

It’s no secret that my long-term goal is to develop a community-scale composting operation, taking all the food waste from the homes and businesses in my area and processing it locally to feed their neighbourhood soil. This video about a growing community compost scheme in New Zealand hits all the notes: wide-eyed idealism crashing into harsh realities, the pitfalls of scaling from hand-built heaps to mechanical systems, the terror of careful plans unravelling due to unforeseen circumstances, the soul-sapping indifference of officials from city and industry. But all overcome by some innovative thinking and a lot of community action. It’s a rollercoaster, to be sure, and a fun watch even if you have no interest in compost.

But we do have an interest in compost, so it’s all very intriguing. I found myself pausing to examine some aspect of their operation and wishing I could zoom in and get a closer look. Take this, for example.

It’s the sort of grinder you see being used to crush metal waste into smaller pieces and I’ve often thought it would be much better for processing food waste than the standard garden chippers and mulchers. But I’ve never seen on at this scale. They’re either massive bastards in recycling plants or tiny hand-cranked fripperies. This looks to be exactly what I’m after - the goldilocks of grinders - but it’s only shown for a second.

I guess I should just email them, but if anyone knows what this is called and where I can get one I’d be most grateful.

Anyway, there’s more about the community compost scheme on their website. Next time I’m visiting my relatives over there I’ll have to pay them a visit!

Long read: These fungophobic isles

I enjoyed this article about British culture’s complicated relationship wth mushrooms. I’d always assumed being extra cautious about wild fungi was a perfectly sensible thing, but of course other cultures are much more laissez faire.

Thanks again for reading! Last weekend I received a truck-load of horse manure which is currently sitting under a tarp waiting for me to decide exactly what to do with it. This is my first experience with poop from an animal larger than a rabbit so it’s all very exciting!

See you in a period of time somewhere between seven and twenty-one days,

Your friend in rotting vegetation,

Pete Ashton

Hi again, and thanks for subscribing to my experiment in compost newslettering. On reflection, last week’s missive was a bit of an incoherent jumble, but I’m not too worried. I’m figuring out how to write about composting in a way that isn’t yet another “how to compost” guide. There are going to be some experiments. Some will be better than others.

One issue is I have so much to talk about but also so much to learn. I really feel like I’m at that point where many would consider me an expert while others would see right through my lack of knowledge and experience. It’s a nice place to be, if I’m honest, because I know I have a good foundation of knowledge and a long road ahead of me.

Anyway, what’s up with the heaps?

This week I emptied the middle bay that in theory should have been finished compost. It was not finished. Patches were done but it definitely didn’t look like it had been started in September 2022. I would say it’s a disappointment, a heap that has failed. But a lot has happened to me in the last year and this heap was, in a way, a reflection of that.

I had Long Covid for the last 6 months of 2022. It wasn’t totally disabling but it did significantly reduce my capacity for doing anything physical or mental until the fog lifted over the Christmas break. Getting through the week was more important than composting, so I was at best just dumping stuff and leaving it there.

Over the winter it dried out with the base of the heap becoming compacted. I should have been turning it but I still didn’t have much energy. Then, as 2023 began, both my parents died, first my dad and then my mum. I learned very quickly that grief is just weird and confusing and my society does not prepare us to deal with it. My grief mostly manifested physically and was a bit like having a Long Covid relapse. Just exhausted all the bloody time.

While the allotment did provide some solace - I remember just sitting watching the trees and birds and it feeling good - I obviously didn’t have the oomph (as mum would have put it) to get in there with a pitchfork. Composting again took a back seat.

Since July things have been better and I’ve refocussed on the composting endeavour. I’ve been working with a few community gardens and food redistribution groups in Birmingham on improving their composting systems and of course invented the hexagonal compost bay, talked about last issue.

But when I emptied the middle bay and saw how poor it was, despite my records showing a perfectly good mix of ingredients, I was struck by how it was a reflection of my life over that period. I sometimes say that my art practice turned into a composting practice over the pandemic and I’m just waiting to see what “compost art” looks like. I don’t really expect this to happen, but this pile of semi-rotted organic matter could definitely be considered something of a portrait. It reflects my physical and mental state over that time in a way I might struggle to express in words.

I call this piece “so very tired, all of the time”

It’s not a write-off by any means. The wonderful thing about composting is it will eventually rot down given enough time. It’ll make a perfectly good mulch as it is and given a couple more months in the “done” bay it might even be considered compost by Christmas.

Great composters of history

Adela Curtis

Liz Howlett left a nice comment on the last issue and mentioned her research passion, Adela Curtis, who wrote a pamphlet about composting at the outbreak of WWII when the population was being encouraged to “dig for victory”. Liz promises to send a copy of the pamphlet when she’s back from her research trip to the USA which she’s documenting in a newsletter. Looking forward to it!

Do you have a favourite composter from days gone by? Let me know!

Long read: mycoremediation

One of the first things you come across when you get into composting is the magical power of mushrooms and how fungus will save us from the wreckage of industrial modernity. I love Paul Stamets as much as anyone, but I also have a healthy skepticism for woo and the kind of evangelical fervour that those desperate for a solution to our seemingly unsurmountable woes can be susceptible to.

Finding Hope In The Dark Power Of Fungus tells of such a journey from true believer to mild skeptic as Joanna Steinhardt joins a group of mycoremediation enthusiasts who are convinced they can solve humanity’s waste disposal problems with the right fungus, but who never seem to be able to get past the proof of concept. It’s a great snapshot of the last decade with some really keen observations on the human condition and it’s relationship to waste.

Illustration by Taehyoung Jeon taken from the article.

My big issue with this stuff is the idea that we’ve stumbled upon a simple solution. All we need to do is dump a load of the right fungus into our trash streams and let “nature” do its thing to eradicate it, as if the fungus is a magic wand that will make the oil and plastic and toxic shit just disappear. But solutions are never simple. For a start, in nature fungi doesn’t work alone. Decomposition is a team effort with bacteria, worms and plants all doing their part too. As we know from composting, the inputs and outputs might be simple, but the process is a massively complex web of micro and macro interactions over which we only have the illusion of control.

But that’s not to say the mycoremediation movement is pointless. A burst of unsustainable hype is to be expected at the start and many fascinating things have been learned. But it also provides a spiritual purpose for those feeling lost in the mess of late-capitalism. As Steinhardt says:

I see a similar thing when talking to people about composting. People bringing me buckets of their kitchen scraps aren’t going to save the planet - we need massive systemic change for that - but maybe it serves as a “culturally meaningful domestic intervention”, and maybe that’s OK.

via Patrick Tanguay’s Sentiers.

Cats on compost heaps #2

Because where there’s heat and a good chance of mice, a cat will be found just chilling.

Here’s Erica, settled on Karen’s compost heap. Originally posted to her Mastodon, which is bascially full of photos of cats, as it should be. Added here with permission. Thanks Karen!

Send me your photos of cats on compost heaps. I want them all.

Big question: Should the compost heap touch the soil?

I’ve been thinking about this a lot over the last few months as I’ve worked with people to establish their compost bays. I’ve always thought that the heap should be built on soil so that the micro-organisms and creatures in the soil can get in and do their work. But while this makes sense for the cooler, resting periods, I’m not so sure it matters for the initial hot composting part. I’ve seen this work perfectly fine on concrete slabs, in bins and even in large plastic bags of damp hay. And of course there’s the wormery method which always seems to be suspended above the ground so the run-off liquid can be saved.

There are also good reasons to compost on a solid surface. Easier to pest-proof, easier to shovel, easier to deal with aeration and drainage.

All my heaps sit on rat-proof mesh directly on the soil, but I’m coming around to the notion that those first couple of months at least are best on a solid surface. Then, once you have a good mulch, move it to rest on soil so the worms can get in.

What do you think? Is soil contact essential throughout?

That’s it for this issue. As always, let me know what you think and send me anything composty that others might like to see. I’m also interested in guest writers – tell us about your heaps! info@aerobicdigest.email is the place to send it.

See you in a period of time,

Pete Ashton

Thanks for subscribing to my weird experiment in compost newslettering. Sixty of you are getting this third email, which I visualise as a decent audience were I talking in a church hall, and I’m very happy with that.

In theory I do my composting once a week on a Sunday afternoon. In practice I don’t always have the time or energy (the long tail of Long Covid casts a long shadow) and the stinky boxes start to build up, as they have this last fortnight. This weekend I had both time and energy so got to work on what turned out to be a new pile. And because I’ve set myself a rule that I’ll only write this newsletter after a session on the allotment, I’m going to tell you about it.

Last time I’d filled the current receiving pile to the brim so it’s now formally resting for the next couple of months. This means I now have three full bays and a significant amount of material with nowhere to put it. What I should do is empty the bay with the oldest heap of presumably finished compost, but I forgot my drill – another reason to put latches on those original bays. One day I’ll re-do my own composting system with everything I’ve learned from making them for other people. But not today.

Thankfully the bay that was due to be emptied into the middle resting bay was the newer…

Hang on. This is getting confusing. Let’s see if a diagram helps.

A and B are my receiving bays. Once A is filled to the top I let it rest and start filling B. It takes me at least a couple of months to fill a bay so while B is being added to, A is resting. This means I turn it in on itself once or twice to oxygenate and move the edges to the middle, but otherwise let the hot thermophilic bacteria do their thing.

Once B is full, A is ready to be decanted into C which will have settled to about half the original volume. A is now freed up to be my receiving bay again while B has a rest. Once A is full for the second time, B is now ready to decant into C, filling it to the top now.

A rests and B becomes the active receiver until all three bays are now full of compost. A is half done, C is pretty much finished and B is pretty raw. C is now emptied into the Done pile and is ready to receive A.

Make sense? Yes? Great! No? I’ll try again later. Maybe an animation is needed.

Anyway, you’ll notice that the bay B is hexagonal. This is my prototype hexagonal compost bay which I built early in the summer and which has now processed its first batch of muck. I posted it to Reddit in June and should really do a follow-up.

It attempts to solve a couple of issues I have with the square mesh bays you can see on the edge of the photo. The first is right-angle corners: a compost heap radiates from the centre like a sphere, so the corners always compost slower, if at all. Turing these into six 60° corners evens the edges out so they should compost at the same rate (at the cost of a bit of capacity).

Secondly I created a void between the mesh and the slats which I ‘insulated’ with sheep wool. (This is commonly used as a packing material for chilled foodstuffs and I have a couple of sources, though you can also buy it as a garden mulch layer) I’ve found that wooden walls don’t allow air in and eventually rot, but mesh walls keep the first few centimetres of the heaps bone dry. I wanted to see if by replacing the edges with wool it would stay relatively dry while the stuff I wanted to compost would get on with it.

In short, it all kinda worked? I was pleased to see that aside from some tugging through the slats by rodents the wool was intact and mostly dry. Heat-wise, the rounder shape certainly did the business giving a much more even ‘bake’, but the summer sun dried out the south-facing side meaning when I came to turn it in August the left and middle was nice and dark while the right was barely touched. Still, that’s a positioning problem which shouldn’t be an issue now we’re moving into winter. Next spring I’ll move it or build a shade.

You’ll notice it has doors with latches which means I can open it without a power drill, bringing us back to the beginning of this digression. I opened it up and forked everything into a couple of rubble sacks as a stop-gap until I empty the middle bay. It was wetter than I would have liked, probably due to my over-watering after the heatwave, but otherwise nicely done with very few patches of raw hay or card. Definitely ready for the cool resting period, and in only two months.

This freed up the hexagon for all the new material and I pretty much filled it half way. The green:brown ratio is a bit heavy on the green, thanks to the communal wood chip heap being mostly leaves at the moment, but I can fix that later if it’s a problem. I also stuck a spare pipe vertically from the middle of the heap to the lid, as an experiment.

Right, let’s see what interesting links I’ve been saving over the last fortnight.

Video

I find “how I make compost” videos fascinating because I always disagree with something in them. This is a good thing as I’m either wrong, in which case I’ve learned something, or I’m right so can feel smug. And of course there’s no right way to make compost - just different ways.

This is overall a really interesting video and I’d like to dig deeper into his lactobacillus bacteria brewing and figure out what he means by “anaerobic” in this context. But to get the niggles out of the way, he’s not making “garden soil” – it’s a soil amendment. And he’s barely made compost in that time – it’s more of a mulch which will need a while to mature before it’s ready to put seeds in. And that’s fine! Because Fiona (my signifiant other) has no-dig beds, so I can give her fairly raw compost to spread on the top so the worms pull it into the soil.

What is interesting though is the 21-day thing, which is of course perfectly doable. The reason my heaps take nearly a year to be ready is because I barely turn them in that time. If I was out there every other day then I could speed that right up, but I’m not, and even when I am my time is mostly spent mulching and feeding the heaps. But turning is very useful, if you have the time and energy.

Turning mixes everything up so it composts evenly. But more critically it aerates the heap, giving the bacteria plenty of oxygen which speeds up their work. If you can’t turn then there are other ways to get oxygen in there. You could push air through the pile, also known as an Aerated Static Pile which I’m approximating with my perforated pipes (see the first issue).

But ultimately, I don’t need compost in 21 days. With my current inputs I can probably fill four bays a year, so there’s no rush. In the future though…

Cats on compost heaps

In what I hope will be a occasional series, here’s my neighbour Charlie looking startled.

Compost heaps are warm and attract mice so of course cats can be found on them! If you find a cat on your compost heap, send it my way!

Timelapse

As someone who used to teach photography and make art with cameras I’m constantly thinking about how to visually document the composting process, given it’s a) not very pretty and b) incredibly slow. Today I propped my phone pointing down into the hexagon bay and recorded a timelapse of me emptying it. It’s not that great, until you notice all the bugs finding themselves suddenly exposed to the light and desperate to escape, which probably wouldn’t be so obvious at normal speed.

Soil as metaphor

301 Permanently Moved is Jay Springett’s weekly... address, I guess? It’s a short five minute (301 seconds) audio/video lecture which he also posts the transcript of. Anyway, when he posted one titled Tend Soil it caught my attention, because I’m always looking out for people who aren’t deep into the whole permaculture thing using these sorts of analogies (although to be fair he’s a big solarpunk advocate).

Here’s Jay sketching out a manifesto for creating a sustainable base and sanctuary for the online artist.

Nice. Listen / watch / read the whole thing here.

That’ll do for this issue, I reckon. Next time I might write about Hugelculture, since there’s a few links sitting in my notes and it’s such a great word. Or I might not!

If you have come across anything interesting to do with composting, send it to info@aerobicdigest.email or @ me on Mastodon where I keep tabs on the #compost tag.

See you in a period of time somewhere between a week and a month!

Pete Ashton

A birthday card I received this weekend, ostensibly from the worms in my compost. (I suspect my sister-in-law actually made it)

Composters are always banging on about getting the mix right, the ratio of greens and browns and wets and dries and so on. Some composters take samples and put them under a microscope to see what life is there and adjust their mix accordingly. Like all pursuits that lend themselves to nerdery there’s a lot of scientific methodology available. But you can also just leave it alone. It might take a few years but eventually everything that was once alive will turn into plant food. Developing a composting practice is about finding your comfort zone along that spectrum.

One of the things that appeals to me about composting is that it’s a massively chaotic process that produces relatively consistent results. My inputs are fairly broad. (I aspire to One Rule Composting, the rule being “was it recently alive”, though I avoid raw meat, mainly because my heap is in a communal allotment and that rotting meat smell is a bit much. If I was in the middle of nowhere I’d be taking all the butcher’s scraps.)

But I digress, my inputs are fairly broad and thorough circumstance will often skew in a particular direction. Last year a mishap with bread collections at the bakery where I work provided me with a large amount of stale bread. This gave my heap a very yeasty vibe at first, but by the end it was black earthy mulch. Last month I was given 36 sacks of shredded laurel branches and leaves (with the most amazing almond smell thanks to the cyanide they gave off - transporting them involved keeping the windows wide open!) which now make up about a third of my nearly topped-off current heap. Thanks to a much better charity donation system at work I hardly have any bread anymore, but I bet you the end results will be the same black earthy mulch.

The process of composting always takes me by surprise too. I expect steady shrinkage as the heap settles and bigger pieces are broken down, but suddenly something will optimise and whoosh, it drops 30cm seemingly overnight. Part of me wants to do the science and optimise, but I also enjoy the ignorance of following the progress of organisms that might as well be from another planet.

The time scale exacerbates this too. I once described composting as like baking a cake really really slowly. I tend to have three heaps on the go, started three or four months apart. Any lessons learned won’t be put into practice for close to a year so progress is slow. I’ve been doing this “properly” and keeping notes since April 2021 and am about to cap off my ninth heap. In any other pursuit doing something nine times is basically nothing. I have so far to go.

That’s part of my motivation for writing this newsletter - I’ve learned plenty from others who’ve made way more than nine heaps and I think I know enough to pass on to those who’ve made way fewer.

The science of composting

This overview of compost science cropped up on the composting subreddit (which used to be really active and useful before the moderator strikes and is now… less so - nice one Reddit…) and I was surprised not to have come across it before. With the caveat that, as I said above, I am not a scientific composter, it seems like a pretty good introduction for the layperson who wants to get deeper into this stuff but finds the more technical books a bit daunting.

Biology gives a survey of the life that lives in the heap, from the different bacteria for different temperatures to the food chain of big bugs that eat medium bugs that eat tiny bugs.

Chemistry dives into the carbon:nitrogen ratio and brings some sanity. I didn’t think I’d be interested in the chemistry of the heap (no pH measures for me) but this brought some real clarity.

Physics deals with the size / air conundrum, where you need a decent size to get the heat, but gravity will squash the oxygen out, so you won’t get the heat. How do you maintain this without turning your pile all the time?

What does the river want?

James Bridle is an artist and activist whose work has crossed over with my interests a fair bit over the last decade. This talk he gave - What does the river want - might seem a bit of stretch for a composting newsletter as it’s not about composting at all, but I found it hit some of the same things I think about when I think about compost, namely that this is a collaboration with a life form that I have no way of communicating with.

Bridle’s current book (which I’ve skimmed the start of, because my capacity to actually read books all the way through just vanished in the pandemic and never came back) is called Ways of Being and it responds to the incoherent nonsense babbled by fools about so-called Artificial Intelligence (don’t get me started) by looking at the other intelligences “that have been with us all along” - animals, plants and natural systems that show complexity and knowledge.

But, as the talk makes clear, it’s not just about looking at the world and seeing patterns of intelligence we can learn from or exploit. It’s something more profound, a way of perhaps undoing the habits of extractive colonialism and capitalism of the last few hundred years, of bending the world to our whims. Planetary systems are in the process of attempting to correct humanity’s misadventures and it would be in our interests to work with them, not against them.

Anyway, well worth 35 minutes of your time.

See also Donna Harraway’s Staying with the Trouble: Making Kin in the Chthulucene, another book I love dipping into and hope to read properly one day. As Wikipedia quotes from the introduction:

Be sure and make oddkin with your compost heap this autumn.

That was the second Aerobic Digest, always a tricky one after the thrill of new beginnings. Let me know what you think and send me stuff to include! Videos, essays, resources or even your own composting stories - I’m open to all ideas at this stage.

See you in a week or so, but definitely within the month.

Pete Ashton

I start a fresh heap with a decent layer of wood chip into which I place three or four short pieces of drainpipe, about 60cm long, into which I’ve drilled a bunch holes. The pipes run from the side mesh of the heap structure to the middle, drawing fresh air into the core of the heap.

These are then covered in more wood chip so the holes don’t get clogged, and we’re ready to start properly.

My input streams are pretty constant. Our rabbits give me a big sack of dirty hay and poop once a week, the allotment gives me weeds through the summer and finished plants in the autumn, my small network of eight bucket-fillers give me their kitchen scraps and I raid the food waste bin at the bakery where I work for veg peelings and and stale bread that didn’t make it to the food bank. If the inputs are dry I add water. I top this off with woodchip from the communal allotment pile to keep the smells under control and a good few litres of my own urine, because of course I do. It’s a weekly job and I record any unusual additions and changes as I go.

I’ve begun to see composting as a metaphor for pretty much everything, so it makes sense to approach this newsletter in the same way. Every week or so I will add some stuff to the mix - a video I’ve liked, an article that taught me something, a conversation with a fellow enthusiast, a report from elsewhere, an experiment which worked or failed interestingly. I’ll also be asking my fellow mulch-nerds to contribute their stories and ideas. After a decent period of time there’ll be a pile of stuff which you, the reader, will have added to the other stuff you read and watch and built your own connections. I hope it feeds your mind, accelerating the grown of new ideas which, once you’ve harvested them, can be added to your own pile. (If you have your own internet pile, be it a blog, video channel, social media thing, or whatever, and it’s about composting, let me know.)

That’s probably my favourite thing about composting. We throw a load of ostensible rubbish in a pile and stuff happens to turn it into nutritious plant food. We can guide the process by controlling the mix, keeping the bad stuff out and maximising the good, but ultimately it’s out of our control.

Hopefully that sets a decent tone for this endeavour. As Ze Frank once said, let’s start this shit up.

First turn of a half-composted steaming pile, ready to be shovelled back in the bay.

Video: Making compost at scale

Get past the somewhat hyperactive intro from Jesse and this two-parter has quickly become one of my favourite composting videos, because despite the scale it all feels so achievable. Most of the large-scale setups I see are dauntingly industrial but this just uses a large plot of land and a digger to turn it. Even the pest control solution is inspiring – they left some dead trees standing so the local birds-of-prey can spot any rats and kill them. Part one, part two.

Art: Markus Wernli

Illustration from “Soil Trust: Belonging-to-the-Field (回歸田嘢)”

I was telling my artist-friend Nikki about my recent conversion to the cult of composting and she suggested I check out Markus Wernli who has a research-based practice in Hong Kong. The first project on his website, Soil Trust, is the most obvious overlap with my interests, but there’s plenty to deep-dive around rethinking waste, particularly human waste.

Education: Argent College’s rooftop garden

I came across this project when someone sent Hunt Emerson’s posters to the local composting WhatsApp group. I’ve loved Hunt’s work since I was a kid in the 80s so was excited to see him drawing my latest passion.

Argent College is part of the Ruskin Mill Trust - an educational charity for young people with autism - based in Birmingham’s Jewellery Quarter. They have a rooftop garden with a Ridan “Dragon” composter. There’s a good case-study report on the Ridan website which goes into more details.

I’m intrigued to see the worm farm in the basement. My instinct is that the worm stage of the process should be in contact with the soil, but this isn’t the first time I’ve seen it done indoors. It makes a lot of sense and I’m sure it smells really nice in there.

That’ll do for now! The Aerobic Digest will return in a period of time yet to be determined but no sooner than a week and definitely within the month.

Pete