First Compost at the City Garden

Thank You!

A huge thanks to everyone who has begun composting with us! We’re excited to be growing and hope to continue to bring in more friends and neighbors — we have lots of plans for our compost! We want to:

  • grow flowers at our downtown LRA plot using compost as the base medium

  • share finished, screened compost with our members

  • feed the red wiggler worms we’re breeding in our basement (more on vermicast another time)

  • keep 1k lbs of food waste per week out of our landfills (spread the word!)

The Big Event

Thursday was our inauguration of our pallet compost bin and we’re so excited to have begun composting on the site which we plan to transform from an abandoned mostly-concrete slab to wood-framed raised beds for flowers. We’ve got a long way to go, but the path is paved with buckets of compost (as they say).

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The garden as we took it from the land reclamation authority (pallets are ours)

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Preparing to mix the first food scraps

Making compost requires a mix of materials that encourages aerobic microbes — not just bacteria but also fungus, actinomycetes, and a diverse set of small animals — that collectively turn the food waste into stable finished compost.

Mixed correctly, the pile will have a carbon to nitrogen ratio of 25-30:1 and be composed of a range of particle sizes to allow air, water, and microbes to move throughout. We take our mixing very seriously and use Cornell’s compost calculator to help us get the ratios right. At present we use chipped wood from local tree-trimming services and coconut coir as primary carbon sources. They’re pesticide-free and make a stable, pH-balanced mix that crumbles nicely once finished.

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A layer of food (nitrogen) over a layer of carbon (wood/coir)

Once it’s mixed we check the moisture level (like a wet sponge) and close up.

A properly-formed compost pile will generate enough heat from microbial action to heat itself to near-pasteurizing temperatures. Our goal is to keep the pile at ~135 for 4 days, which is sufficient to kill most weed seeds (although not always tomatoes, those are really hardy!) as well as knock the levels of harmful bacteria down to insignificant levels. The minimum pile size is roughly 1 cubic yard of material, or 200 gallons, so the more composting supporters we have the better for this step!

After the pile has cooked a bit we turn and, soon, will feed this pre-compost to our worms. The majority we re-mix, adjust water if needed, and let heat again. After a second heat phase we set it aside to cure, allowing the remaining microbes to gradually finish their work before sifting, sharing and applying to our garden.

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Our 1/2 inch trommel (off its stand)

We sift with trommel screens made from unusable bike wheels (huge thanks to Mike’s Bikes & B-Works STL) and hardware cloth: 1/2 in, 1/4 in, and 1/8 in (for vermicast, to catch worm cocoons).

I love talking about compost, so send questions or comments to matt@blhfarm.com.