Almost all of my products are excellent to incorporate into compost, but there are a few that come to mind as being at the top of the list. They will not necessarily make a poorly built compost into a good compost, but they can greatly increase the speed of decomposition and improve the final product:
1. Effective Microorganisms (EM) - Inoculating the compost with these beneficial microbes will speed up the process and contribute to a decomposition that is more controlled/less oxidative so that nutrients are better retained. Odours are also greatly reduced. EM can be mixed with 100 parts water and sprayed onto compost until the desired moisture is obtained. It could be done monthly or even just once when building the compost. As usual, this can be mixed with molasses, sea minerals, kelp, and/or fish to improve the effectiveness of the EM.
2. Glacial Rock Dust - This is an incredible addition to the compost. Just sprinkle it in as you build the compost or work it in from the top. The nutrients have an opportunity to bind with the organic matter and are more effective when they are eventually incorporated into the soil. The dust will also improve the composting process. Different sources say to apply anywhere from 2 to 50 pounds of dust per cubic yard of compost. If you have just a small compost of a yard or two, it's definitely affordable to go for the 50 pounds. If you're composting on a larger scale, you can use less and still be sure to receive some benefit.
3. Penergetic for Compost - Applying this homeopathic product at 40 grams/cubic metre of compost will stabilize the composting process and help to bind nutrients. It is very economical. It is easiest to mix it in water and apply it that way. It can be mixed with the EM above, but doesn't go through a sprayer all that well.
4. Naturally-Mined Rocks - If you have determined that you need certain nutrients in your soil, it is great if you can first add them to your compost. Products such as calcitic lime and rock phosphate will bind with the organic matter, just like with the rock dust mentioned above. In fact, it would be entirely appropriate to add a couple of pounds of calcitic lime when building the compost, as it is so crucial to the microbes, but don't add too much unless you have determined that your soil needs it.
These are some of the best products to add to your compost and help to produce an incredible organic amendment for your soil.