Making your own compost is a great way to recycle yard waste that would otherwise end up in a landfill. It’s the epitome of green gardening, and it’s really not that complicated.
The pile should contain about half fresh, green matter (fresh manures, grass clippings, weeds, kitchen waste) and half dry brown matter (fall leaves, straw, last year’s garden). If the manure you collect locally comes mixed with straw bedding, you already have the perfect combination for compost. Mix the green and brown parts together, or create thin layers.
Shredding your ingredients helps speed decomposition. In Colorado, an unshredded pile may take several years to break down, but it will eventually turn into compost.
You don’t need a fancy bin, although that can look nice. If you decide to buy something, make sure it’s big enough. Your pile should be at least 4 feet on a side and 4 feet high. It takes that much mass to keep the interior damp and warm. Any container should allow for some air circulation to bring oxygen to your decomposers. Don’t compact your compostables—keep the pile fluffy.
You want to keep the pile damp… about the same as a wrung-out sponge. Too wet and you’ll generate slime. Too dry, and nothing will rot. You don’t need to add any sort of compost starter, in spite of all the ads. There are plenty of bacteria hanging around to do the job. If you’re in doubt, add a cup of soil for insurance.
Now comes the hard part. Wait. You don’t really have to do anything, other than keep the pile damp. After a few days or so, the pile should heat up inside as the bacteria munch away. If not, check the moisture levels. If things are damp, you probably need a bit more nitrogen: green matter, fresh manure, or even some high nitrogen fertilizer.
Once the pile has heated and cooled, you can turn it to bring the outside materials into the center. (Or, you can use the compost in the middle, and build a new pile starting with the parts that haven’t rotted yet.) If you turn the pile, it should heat up again, although perhaps not as hot as the first time.
You can use compost at any stage. Just remember that if you dig partially-rotted plants into your soil, they will tie up some of the available nitrogen as they finish decomposing.
There are a few things that do not belong in a compost pile. As I mentioned earlier, manure from animals that eat meat (such as dogs or cats) is unsafe. Avoid meat, fat or bones—you’ll attract some unwanted critters. While eggshells are acceptable in areas with acidic soils, most Colorado soils are overly blessed with calcium. Don’t add more. (To tell if your soil has lots of calcium, add a few drops of vinegar. If it bubbles, you’ve got calcitic soils.)
Don’t add diseased plants. Many diseases are carried in the soil. You’ll just spread the problem. Potato peels don’t belong in the compost bucket for this reason. Most commercial potatoes are contaminated with scab, a disease that won’t hurt you, but will affect your potato crop yields. By the end of the season, tomato vines are frequently infected with one of the tomato blights. If you aren’t sure they’re 100% healthy, dispose of them elsewhere.
And finally, don’t add plants that have gone to seed. Chances are, your pile won’t get hot enough to kill those seeds. You’ll just be introducing millions of weeds that you’ll have to contend with next year.
Finished compost smells like good earth. It’s dark brown and crumbly. To a gardener, it’s worth its weight in gold. Compost is the ideal way to keep your garden green.