- Prepare compostable materials with a good ratio of carbonaceous to nitrogenous materials. This is commonly referred to as the ratio of “browns to greens”, though this is potentially misleading as certain “greens” are actually brown in colour. “Greens” are most commonly veggie scraps, kitchen scraps, lawn trimmings, manure and coffee grounds whereas “browns” are usually sawdust, autumn leaves, hay, cardboard or paper.
- While collecting the materials, chop up any pieces which are too big (whole fruits, whole sheets of cardboard etc) so that the pieces can mix well with the rest of the compost.
- Add 2 parts of greens to one part of browns to your tumbler. Some people add one part green to one part brown and that is also okay even if overall composting temperatures might be cooler pile.
- Add 10% of soaked biochar by volume; in other words for 3 gallons of composting materials (11 litres) add 1.2 quart of of biochar (1.1 litres). You can let it soak in a pail with enough water to cover it while you are preparing your materials or even the previous days.
- Add a little water to the compost pile. Some people prefer wetting the browns before adding them to the pile instead, roughly half their volume on water. The compost should feel damp but should not drip water if you squeeze it in your hand.
- Mix a quart (1 litre) of finished compost into your pile so as to inoculate it with microbes. If you do not have ready compost you can collect a few handfuls of forest soil.
- Large compost piles can be built out of wire mesh or wooden pallets, or can be simply piles on the ground covered with tarps but they must have a minimum size requirement of 3ft per side (1 meter cube). Smaller piles will likely require an insulated tumbling composter like the one available on our shop page.
- Aerate the compost twice per week for the first three weeks, and once per week afterwards, this means rotating your tumbling composter or restacking it with a pitchfork, according to the type of system you have.
Biochar amended compost tends to compost hot. Expect the compost to produce a significant amount of heat. The heat comes from aerobic decomposition, and is a good thing. Hot compost kills weed seeds and pathogens. Core temperatures can reach as high as 68˚C / 155˚F
The compost should take approximately 8 weeks to finish and the temperature will slowly decrease until it reaches room temperature. If possible, it’s best to let the compost sit for another month for ‘curing’. This stabilizes the compost and favors fungal growth.
- Your pile smells: check there isn’t too much water, add some browns, ensure you are tumbling regularly and that the aeration holes of your tumble are not clogged.
- The temperature is too low: add some greens (mainly coffee grounds). If the outside temperatures are freezing, cover the pile inside the tumbler with a pillowcase filled with biochar
- Your pile is dripping water: add sawdust or drain the excess liquid
Items to exclude from compost
Avoid the following items, due to the risk of fouling the compost, producing pungent stench, and attracting pests:
- Fish (a small quantity of fish bones and scales can be added if you add more carbonaceous material, and if you bury these deep in the middle of the pile)
- Eggs (egg shells are fine, just crush them well)
- Dairy products
- Invasive weeds
Invasive weeds can be used if they are first burned, steamed, or boiled to ensure that they are totally dead. Otherwise, they can propagate using the compost.