Partners in Slime: Thermal Composting Experiments in Hackney Downs, blog by Hari ~ March 2021


Last spring & summer I got inspired by my friend Jack’s composting antics at the small market garden they run as part of Growing Communities’ Patchwork Farm. During the first Covid lockdown many community kitchens and cafes had turned their attention to providing food for mutual aid efforts locally, and were thinking more about their foodwaste and how to dispose of it sustainably.

Maybe it was because other waste collection services took a hit during lock down (remember the piles of uncollected rubbish bags blowing through empty streets throughout March and April?) or maybe this was a moment of increased consciousness about food justice, waste flows and soil health, but Jack suddenly found themself inundated with foodwaste collection requests from all over East London. They spent their days cycling around like a giant human-worm, transporting trailerfuls of vegetable and fruit peelings to their growing site, shredding and mixing it all up with woodchip and water to make compost. When Jack started to run out of space in their 3 bay system, I offered to share a thermal composting method I’d learnt from a course by Dr Elaine Ingham.

We used thick wire mesh to construct 1m tall composting cylinders (a quick, cheap and effective way of making composting containers) and mixed the food waste with manure, green waste, woodchip and water to raise the temperature to around 60-70 degrees C. We also both invested in compost thermometers, and felt extremely satisfied with our matching ‘wands’ (pictured).

After a week, the middle of the pile (where it was hottest) had turned into dark crumbly compost and needed to be turned, allowing oxygen in to support aerobic microorganisms to do their incredible decomposing work. This was when things got really hottt, turning these enormous steaming piles multiple times, in the full heat of summer, but it also gave us energy, and excitement to be making compost on this scale, transforming waste material into nutrient rich soil for urban food growing.

Last winter and into spring 2021, Compost Mentis took on some of Jack's food waste collection rounds, composting kilos of vegetable scraps alongside local residents’ food waste at Bethnal Green Nature Reserve and at Forest Farm Peace Garden in Hainault. In these sometimes cold & isolating times, we have been finding comfort, healing, life and warmth in the human and more-than-human entanglements that form around these steaming piles. It is a kind of alchemy and offering to a future world.

2 queers with matching t-shirts wield long metal thermometers in a garden in a residential area, looking pleased with themselves.
person kneels in front of large round thermal compost pile, inserting a thermometer and reading the temperature. A 2nd thermal pile / cylinder is in the background
a round thermometer in a brown woody compost pile, reads just over 60 degrees centrigrade
cut out image of a bike with trailer containing full black bin bags
a pinkish-red 3 bay composting system, with lids open, exposing the composting processes inside.