Large compost bays are great for hot-composting as large amounts of materials can be added in one go or over a few days, meaning hot, fast composting is possible. Wooden bays can be bought, or built for free using second-hand pallets, or wood and wire mesh.
How it works
After building the bay it is filled with brown and green materials, layered or mixed together. If the bay is filled on one day, or over a few days, the microbes and other microorganisms (tiny creatures) quickly get to work breaking down the materials. This produces heat, and temperatures can rise to 65 degrees C within a couple of days.
These temperatures kill plant diseases and break down weed seeds. If the heap reaches hot temperatures it is more important to check it every few days for moisture and oxygen. Water vapour (steam) is released, which can dry out the pile, slowing it down. Pockets of materials can become anaerobic, so it is important to mix or turn it. Follow this for troubleshooting (Link)
After a few days at a high temperature, it can be good to turn the heap to move the materials on the outside of the heap into the centre. This gives a more even end result, and will make sure any weed seeds are heated up and destroyed.
After some time (can be days or weeks depending on materials/moisture), the temperatures will start falling. The compost can now be left to mature. It is ready when it smells earthy, and looks dark brown and crumbly, without any of the originally greens recognisable.
Pros
- Can be built for free from pallets.
- Great for allotments or large gardens.
- Large volume make it easier to reach high temperatures, destroying weed seeds.
- Lots of compost can be produced quickly.
Cons
- Take up more space, and can look scruffy depending on how they are built.
- To make hot-compost requires a lot of ingredients over a few days.
- Can be heavy work to turn and aerate.
- Can be hard to rat proof open bays unless factored into the original design.
