By Judy Elliott, master composter, Colorado State University Cooperative Extension, Denver County
Nature's ultimate form of recycling, composting, is for everyone. One of today's prime environmental concerns is the disposal of plant residues harvested from all our yards. Twenty percent of trash is yard wastes. Don't clog our waste disposal system. Convert plant residues into "organic gold" to loosen your soil and grow better plants.
Composting needn't be difficult if five basics are kept in mind: nutrition, moisture, air, surface area, and volume.
The microorganisms that break down plant residues need a 50:50 nutritionally balanced diet of "greens" and "browns." Green plant materials are higher in nitrogen and include fresh leaves, soft stems, spoiled plant foods from the refrigerator, small amounts of manures from plant eating animals, deadheaded flowers, and weeds that have not set seed.
Note that grass clippings are best left on the lawn where they will recycle organic nitrogen back into new grass growth. If used in compost, they too are a nitrogen nutrition source.
"Brown" plant residues supply carbon and include dead grass raked from lawns in spring, dried leaves, straw, woody twigs cut up into small pieces, and tough stems of flowers and vegetables.
Moisture is essential for life and the microorganisms that break down plant wastes are no exception. Ideally, the moisture content of composting plant residues should feel like a "wrung-out sponge." Regulate the amount and frequency of watering to maintain optimum moisture, less in spring and more in the heat of summer.
Air is also necessary to sustain the decomposition. Provide air by stirring, turning, or inserting pipe with holes for air channels. Turning over the entire mass is the ultimate aerator. Fast working microbes require the air supply be replenished by turning or stirring once a week.
An increase in surface area allows many more microbes to "belly up to the table" and speeds breakdown. Chop or shred plant materials into chunks of no more than one to two inches for efficient composting. A mix of fine and coarse textured materials works best.
To build a "masterpiece of decomposition," first chop your green and brown materials into smaller pieces. Make a 4-6 inch layer of browns in the compost unit of your choice. Top with a 4-6 inch layer of greens and a sprinkling of soil or partially decomposed compost. Water and repeat this layering to meet the fifth requirement for efficient composting, a minimum volume of 3x3x3 feet.
During the warmer months, plant residues compost in one to two months. When finished, compost has an earthy, pleasant aroma, and is crumbly to the touch. Use compost to prepare the soil for planting any plant, or gently work in around established perennials.
Composting allows you to take an active role in preserving the environmental health of your community. Environmental action truly does start in everybody's yard.
Photo: Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010