When Is Compost Finished?
Knowing when compost is ready to use is about as precise as knowing when homemade chili is ready to eat. It's done when you feel that it's done. Because the outside layers of a pile usually never completely decompose, the best place to check on the decomposition progress is inside the pile. While there is a fairly precise definition of what constitutes "finished" compost on the commercial side of things, homeowners usually determine for themselves with their own standards when the contents of the bin are ready to use. Commercial composting operations have ways to measure the C/N ratio (usually around 15:1), the volume reduction (about 50%) and the weight reduction (about 50%) of the pile. For homeowners, the decision to start using the compost is a very subjective one.
[Photo - Showing pile of finished compost]
Finished compost is usually dark brown or black. It can be quite lumpy, but all the ingredients used to build the pile have lost their individual identity. The finished product looks like commercial potting soil with lumps. One test, if you want to take the trouble is to turn the pile to learn that the temperature does not exceed 110øF, the sign that microbial decomposition is finished. However, compost does not have to be completely decomposed to be useful around the yard. For example, compost that is only 50% decomposed and is coarser in texture with larger lumps and clumps is useful as a mulch or as a soil amendment anywhere in the yard or garden. It continues to decompose slowly, but does not develop enough heat to in any way harm the plants. However, do not use compost that is not completely decomposed as a medium for starting seeds. A seed starting mix should have only finished compost. Some seeds tend to germinate poorly in only partially decomposed compost.
Use a sifting device to acquire some compost that is fairly fine textured, perhaps to mix with peat moss for a container. In Chapter ## we identify several sources for commercial compost sifters and have several designs for building your own. To produce the most wonderful, fluffy, fine compost you've ever seen, run the finished compost through a chipper/shredder. The final product can be used in any application described in the next chapter.
[Photo - Showing sifting finished compost]
Storing Finished Compost -- If you do not use all the finished compost you produce from the pile, store it someplace out of the weather. A simple tarpaulin cover will do the job. It is very important to avoid exposing the finished compost to rain which will leach out much of whatever nutrient value the material might have. However, exposure to rain and snow does not diminish the value of compost as a valuable soil conditioner. Its capacity for holding moisture, for helping soil to drain, and for reducing soil compaction is not affected.
FREQUENTLY ASKED QUESTIONS ABOUT COMPOST
Are oak leaves and pine needles safe to use in the compost pile?
Absolutely! Both are acidic in their raw form but when composted the resulting material is neutral. They may take a bit longer to actually become compost, but if you have lots of oak leaves and/or pine needles; go to it.
Compost is the by-product of the natural decomposition of organic materials such as leaves, grass clippings, weeds, and other organic matter found on residential properties. It looks just like the dark, almost black humus found just under the layer of leaves on the forest floor. Homeowners who choose to deposit accumulated yard waste in a pile in a corner of the yard and allow it to decompose on its own not only reduce the pressure on the local trash collection and landfill systems, but they also acquire this extremely valuable product that has many uses around the landscape.
Compost is the result of the activity of billions of microorganisms that break down the nitrogen and carbon in yard waste into humus. Given a supply of oxygen and some moisture these microorganisms go to work on organic materials such as leaves and grass clippings and transform them into compost. All a homeowner has to do is create an environment for them that has the raw materials--nitrogen, carbon, air and moisture. Do this by loosely dumping leaves, grass and other yard waste into a pile. Now let’s talk about piles.
Two Ways to Make Compost
There are both "active" and "passive" methods for making compost. Because serious gardeners have long known the value of compost and use it generously in their gardens, they are often anxious to produce it rapidly. They use the active method, actively managing the pile to hurry the decompostion process. This involves turning the pile of accumulated yard waste every so often to introduce more oxygen into the pile and boost the activity of the microorganisms.
However, for yardeners who are looking primarily for a method to deal with their yard waste the passive method of composting is best. It involves simply piling the materials and leaving them alone. While it takes longer to produce compost this way, it is a lot less work and the compost is just as good and in some ways better than the compost made using the “active’ method..
This web site describes how to make compost the passive way.