7 Ways to Speed up Your Compost
You want to harvest your compost as quick as you can. Here are 7 ways to speed up the decomposition process.
Balance carbon and nitrogen
Balancing your high-carbon materials with high-nitrogen materials will speed up your compost bin.
High-carbon materials tend to be brown and dry, such as dried leaves, straw and wood chips. High-nitrogen materials are green, such as grass clippings, or they’re colorful, such as fruit and vegetable peels. One item that doesn’t follow that rule is manure from horses and cows. Manure is brown, but it is a high-nitrogen material.
The most efficient composting occurs with a carbon-to-nitrogen mix of about 20:1. That means that you want about 20 times more dried leaves (by volume) than fruit peels.
A chart from Cornell Waste Management Institute shows some carbon-to-nitrogen ratios for typical materials, based on dry weight. The ratios with a small first number are high-nitrogen materials and the ratios with a large first number are high-carbon materials. (Note that some of these materials have a range for their content.)
Here are the carbon-to-nitrogen ratios for some typical materials:
- Poultry manure, from 3:1 to 15:1
- Cow manure, 20:1
- Horse manure, from 20:1 to 50:1
- Food waste, about 15:1
- Fresh grass clippings, 15:1
- Sun-dried grass clippings, 20:1
- Oak leaves, 40:1 to 80:1
- Straw, 50:1 to 150:1
- Sawdust, 200:1 to 750:1
- Newsprint, 400:1 to 850:1
- Corrugated cardboard, about 560:1
The microbes in your compost bin need water, but not too much water. Your compost should be damp, like a wrung-out sponge. If your compost gets too dry, sprinkle in a little water. If it gets too damp, add dry material such as autumn leaves.
The decomposition process works best when the pile has oxygen for aerobic microbes, that is, microbes that use oxygen. When there isn’t enough oxygen, anaerobic microbes (microbes that don’t use oxygen) take over, but the decomposition process will slow down. In addition, the compost begins to smell bad under anaerobic conditions. Using a bin with good airflow or turning your compost every so often will provide the oxygen needed for quick decomposition. Tumbler composters make it easy to get good air flow to every part of your compost.
You can leave your compost bin outside all winter long, but nothing much happens. Think of the plant material in your composter as food in your house. Food in the freezer is preserved for months. Food in the refrigerator is preserved for days or weeks. Food left out on the table or in a compost pail will spoil quickly and start to decompose. With compost, we want the plant material to break down. The decomposition process will speed up when outside air temperatures are warmer.
Chopped plant material
If you put whole leaves in your compost bin in autumn, in spring you’ll still have whole leaves. If you chop up those leaves before you place them in your bin in fall, you can harvest great compost in time for spring planting. To break up the leaves, run them over with a lawn mower or use a leaf shredder. You can even let the leaves dry and step on them—it’s great fun for the kids!
Fill up your bin
In general, a larger amount of material will decompose faster than a small amount.
Cold composting is usually done outside with a compost bin or compost pile. The system relies mainly on microorganisms to break down plant matter and food scraps. Cold composting can take six months to a year to produce usable compost.
Vermicomposting uses composting worms to break down plant matter and food scraps quickly. You can get finished compost in just a few months.
Combining the two techniques can produce finished compost faster than cold composting can, plus you get the benefit of worm castings. See more on the benefits of worm castings here.