With the past two mild winters, we’ve realized that biomass in the courtyard no longer breaks down the way it used to. As a result, the once decomposition of the past perennials nourishing the winter soil for the upcoming spring/summer months no longer occurs and much of it collects in piles throughout the courtyard. Undoubtedly, an acre of land becomes not only difficult to clean up when the weather becomes warmer, but also creates mounds of grass, straw, branches, etc. As a way of addressing this reoccurring problem we’ve recently been experimenting with various composting methods, such as “hot composting”.
What is Hot Composting? This method involves a rather specific construction to allow for optimal decomposition of materials.
Ratio: Considering the fast rate at which we want to break down the material, nitrogen (“green” matter) is necessary. Usually, hot composting calls for a ratio of 25-30:1 (C:N).
Construction: Rather than continuously adding to a pile, a hot compost pile needs to be built all at once. As mentioned before, it should be rather high- and the higher the better! For us, this was the most tedious, since it requires alternating thin layers of green (grass and weeds) and brown (leaves and straw) material 1.5 meters high. This ensures the same rate of decomposition and will prove a richer humus.
Temperature: It wouldn’t be called hot compositing without this factor. The goal is to raise the temperature close to 150 degrees F in order to kill certain pathogens or seeds from decaying material. In traditional forms of composting, many avoid using grass that has gone to seed or weeds due to their tendency to grow once the humus has been placed into the ground. However, on our permaculture site we love weeds since they are nutrient dense and often indicate the state of the soil (i.e. acidity, nitrogen/carbon levels). Raising the materials up to a high temperature allows for the seeds to be killed while still utilizing the nutritious benefits of weeds and grass. It also allows for a quicker break-down of the material.
If you’re interested in doing this yourself, a good way to test the heat is to simply place your hand in the pile- if it’s too hot for comfort, it’s probably at the right temperature!
Placing a tarp over your pile also helps raise the temperature.)
Moisture and Height: These are two important factors in raising the temperature. A taller pile (roughly 1.5 meters high) generates a lot of internal heat, while the right moisture allows for quick movement of microorganisms, and, in turn, drives up the temperature. An important note: too much moisture or not enough makes it more difficult for the microorganisms to move around. Sticking your hand inside the pile is the best way to tell if it’s the right moisture- it should feel like a wrung-out sponge.
Rotation: In order to provide the pile with a lot of oxygen, rotation is vital. Rather than simply shoveling the materials around, proper hot composting methods require an entire layer-by-layer rotation. After letting the pile sit for the first four days, rigorous rotation occurs every two days until complete.
If we eventually produce useful humus from this method, we will have added a lot of the courtyard. Not only will we be able to produce large amounts of humus to nourish our soil, but it will also allow us to make use of the dead bio-mass that collects after the mild winters.
Check our blog soon to see the different forms of compost tea we plan to make next week!