Like most animal products, you probably don’t want to compost bones. This is especially true in a home composting system. Hot systems and Bokashi systems can be used to compost bones, but home systems usually don’t warm enough.
Bones, and other animal products, tend to stink as they rot. Good compost shouldn’t smell. Neighbors downwind can find this really annoying. Rats and mice downwind find it very appealing, and it will draw them to your compost.
Smaller bones, like chicken bones, can be a bit safer. They break down more quickly. Even there, you want to be very careful.
Generally, we don’t recommend composting bones in a home system. Adding bones to compost can add a lot of nutrients to your compost, but for home systems, they also add a lot of potential hassle.
How To Compost Bones
If you decide you want to try to compost bones, here are some instructions to lower the risk of pests and rotting (which leads to the smell.)
- Boil the Bones – Boil the bones to help soften them. Let them boil for a little while.
- Dry the Bones – You can either leave them out for a few days or cook them on the stove.
- Break Up the Bones – You can use a hammer or carefully use a food processor (don’t break your food processor). The smaller you break them up, the faster they will break down in the compost.
- Spread them Throughout Your Compost – You want them deeper into your compost. This will help them break down and reduce the smell.
- Regularly turn Your Compost – You want to aerate your compost regularly (at least 1-2 times per week).
When you go to harvest your compost, look for bone fragments. You may have to sift it. You can return any bone fragments to your compost until they break down.
How Long Does It Take to Compost Bones?
Bone is sturdy stuff. Boiling it and breaking it up help, but it can still take several months for it to break down. The bigger the bone, the longer it will take.
Can I Compost Bones?
Technically yes, but we don’t recommend it. Animal products have risks of smelling and attracting rodents and other pests. If you’re going to try it, make sure to prepare it correctly. Hot composting can help.