Soil Food Web-minded folk tend to focus on building compost piles in the spring and fall, when materials are abundant. As this abundance occurs across different seasons, some forward planning is required. If your goal is to create a pile that is high in microbes and thus has the potential to regenerate soil, in the spring you’ll want a ratio of about 60% “browns”, 30% “greens” and 10% “high nitrogen”. It’s a build-once, turn-three-times-and-then-let-mature kind of thing.

You’re in luck if you happened to stockpile your brown/high carbon materials last fall when plenty of leaves and died-down plant material was around. Add in spring greens and manure for your high nitrogen component, and if you get your pile built soon, it will be ready in time to inoculate those microbes into your soil in the fall. Best case scenario!

But if you don’t have enough browns on hand, then it makes sense to stockpile your greens now in preparation for fall pile building. You will need to wait a little longer for the pile to mature while decomposition takes a break over the winter months, and then a little longer again for the microbes to settle down in the soil profile following spring applications, but it is still well worth it.

Principles for collecting greens for a highly microbial pile:

Diversity, diversity, diversity.
The more diverse the inputs in your pile, the more diverse the microbial community that will come in on, and feed on, those materials. Think cut grass, weeds (yes you can compost them in your hot pile, including the seeds), pruned fresh greens, veggie trimmings.

Dry immediately.
Spread in a thin layer on a tarp and leave in the sun to dry thoroughly. Store in a bag or tote and check regularly for signs of mold.

Kitchen scraps are prime “green” materials.
They can be frozen to preserve the nitrogen and then thawed out the day before you build.

Timing:
– If there is flowing sap and green leaves when you harvest, this is “green”, even if it dries down to brown in colour. Label carefully!

– The first flush of spring growth contains more nitrogen than regular greens. Dry and store separately, and you may be able to use this instead of manure for your high nitrogen component.

Happy hot composting everyone!