The science behind composting is solid. Yard and kitchen waste are made of plants. In nature, plants decompose and return their nutrients to the soil. Other plants feed on those nutrients, growing stronger and healthier. As a bonus, adding compost to planting areas makes plants healthier, and healthy plants need less chemical interventions. Composting also reduces erosion, helps balance soil pH, feeds earthworms and other beneficial soil microorganisms, and it improves soil structure. This is especially helpful in counteracting our areas heavy clay soil.
Many hobby gardeners put off composting, thinking that it will smell bad or attract pests. Others try once, without learning the basics, and end up with a smelly, rotten mess, vowing never to try again. Please try again. The basic rules of composting are simple:
1. Chop plant materials into pieces that are no more than 1½” long.
2. Avoid adding manure, grease, ashes, or soil to the compost pile.
3. Mix equal volumes of nitrogen-rich “green” material and “brown” carbon-rich material.
4. Keep compost as moist as a wrung out sponge.
5. Turn the pile every few days to incorporate more oxygen.
A healthy compost pile should smell earthy, not rotten. A rancid compost pile usually indicates a lack of oxygen and/or too much moisture. At the other end of the spectrum, insufficient water will halt the decomposition process altogether.
There are many different ways to compost. You can dump everything in a pile. You can create a composting ring with chicken wire or hardware cloth. You can also build composting boxes, create a keyhole garden that features a composting tube in its center, or you can invest in a composting barrel that is easy to spin. All of these methods work. You can also compost simply by burying a single day’s worth of kitchen scraps somewhere in the backyard. The bottom line is this: composting can take up as much or as little space as you want. The important thing is to start composting!
Composting takes time
Composting does not happen overnight. Whether you use a barrel, an elaborate wooden box, or a simple pile on the ground, microorganisms and natural processes will cause the middle of the pile to heat up. Ideally, temperatures will remain between 120° to 150°F – you can use an oven thermometer to check. Too much heat may kill the microorganisms that break plant material down into usable compost. Each time you turn the compost pile, you add oxygen for those microorganisms.
When rainy weather arrives, you may want to cover your compost pile with a tarp. The decomposition process will slow, over the winter, put your spring seedlings will get a nutrient boost from your aged compost, for free!
Kate Russell is a UCCE Master Gardener in Santa Clara county. Learn more about garden pests at the South County Teaching and Demo Garden, at St. Louise Hospital, 9400 No Name Uno, in Gilroy. Classes are regularly offered to the public. Learn more at mgsantaclara.ucanr.edu. For more information, visit mgsantaclara.ucanr.edu or call 408.282.3105 between 9:30am-12:30pm Monday through Friday.