Example of a composting drum offered by Clear Air Gardening

Of all the gardening practices you can undertake, composting is one of the most beneficial, as its addition will enhance your garden soil, resulting in robust plants that are more resistant to pests and diseases. Building soil is an essential concept for good gardening, best summed up by the adage "feed the soil to feed the plant." Essential to all soil ecosystems, organic matter is the food for living soil organisms. By adding compost to the garden, you are nourishing the soil creatures, including friendly bacterium, fungi and earthworms, which in turn create more nutrients available to your garden plants. In addition, the heavy clay soils common to our area will drain better, and sandy soils will retain more moisture. Compost also aids in increasing the heat absorption capability of the soil, and helps neutralize soil pH.
With a basic understanding of the composting process, even amateur gardeners can make a pile that produces lots of rich, soil-building compost—often dubbed "black gold."

You do not need a compost bin, however many gardeners buy or build a container to keep the pile neat, and in cold winter climates such as ours, some gardeners swear by insulated rotating drum composters where moisture and aeration can be easily monitored and adjusted. (The San Juan Conservation District sells one that works quite well: call 970-731-3615 for info).

Due to our wild animal friends being in close proximity to homes, I strongly advocate securely enclosing your compost pile to keep skunks, mice, bears and other critters at bay. If you are not able to purchase a drum composter, simple compost containers can be built with chicken wire, wood pallets, bricks, boards, barrels or cement blocks—even a large perforated lockable trash container will do the job. What you need to bear in mind is the container needs enough openings to allow for sufficient air circulation, or else it will smell like rotting garbage. Composting microbes are aerobic, meaning they won't work well unless they have sufficient oxygen.

Whether you are choosing to build a tightly contained or unstructured pile, a minimum size of 3 x 3 x 3 feet, but not greater than five feet cubed, is recommended in order to have enough mass to create sufficient internal heat to decompose effectively. A pile that is properly constructed will not produce offensive odors.

Place your compost area in a well-drained spot (on top of a pallet is also good) that is shielded from wind and any possible flooding. Locate the compost pile within reach of a garden hose, and preferably on level ground. If possible, locate piles under deciduous trees to shade them in the summer when the foliage is thick and to expose them to the warming sun when the trees are bare in the winter.

For efficient decomposition, a compost pile needs a good balance of several main ingredients: "greens," browns," high-quality garden soil, moisture and oxygen.

"Greens" consist of nitrogen-rich materials such as (preferably chemical-free) grass clippings, fruit and vegetable trimmings and fresh steer or horse manure. "Browns" are carbon-rich materials such as chopped autumn leaves, dead (but not diseased) plant material from your garden (no weed seeds!), twigs, straw, and sawdust. Brown materials can be stored easily in a bin for later use (for example, fallen dead leaves or dry weeds, stockpiled in autumn, can be used for layering with fresh green materials the following spring). Particle size has a lot to do with the speed of decomposition. If you don't have a shredder for your leaves and small twigs, try running a lawn mower over them before adding them to the pile, but If the particle size of all the materials is very small, layers can compact and become matted. Chopping the material in about two-inch diameter pieces with a spade will also work.

You can also add eggshells, tea leaves and coffee grounds, but don't use bones, meat scraps, dairy products, or cat, dog, human or pig manure. When manure is left sitting around, much of its nitrogen escapes back into the atmosphere along with a lot of its moisture. Fresh manure is moist, often greenish in color, and smells strongly of ammonia. Although manure can contain weed seeds, composting manure in a hot pile over the warmer months should kill most of them.

Before starting your pile, consider the moisture level of the different compost materials, as well as weather conditions and the time of year. Dry, brown materials need moistening before use. Decomposer organisms, from the smallest bacteria to the longest earthworm, need a consistent supply of moisture for peak efficiency, but excess moisture can lead to soggy, compacted piles. Very moist materials, such as kitchen scraps, can cause areas of compaction and anaerobic decomposition if they are layered too thickly. When oxygen is squeezed out, anaerobic bacteria develops, generating that unappealing "rotten eggs" smell. What you're aiming for is a moisture level equal to that of a wrung-out sponge.

Loosen the soil under the area where your compost pile will be built. As you begin to build our pile, a general guideline is to create layers with equal parts greens and browns by volume. Layering is a good way of estimating balanced proportions. If a pile doesn't have enough nitrogen, it won't get very hot and will not decompose quickly. A pile with too much nitrogen will get very hot and will have a very strong odor of ammonia.

Layers can be two to eight inches thick depending on the particle size and moisture of the materials. To maintain control over density, I suggest layering four inches of brown materials on top of four inches of greens, spray with water, sprinkle on an inch of soil, and repeat. Straight grass clippings, whose high moisture content and small particle size make them mat and compact; should be applied at no more than a two-inch layer at a time. Finish the pile with a brown layer and top it with a two-inch layer of soil. 

The easiest way to ensure consistent moisture throughout the pile is to water each brown layer as you go. Use a hose sprayer for good coverage, taking special care to wet the corners and the edges of the pile. If you wait until the pile is finished and try to soak it from the top, hoping the water will trickle down, well, it probably won't. If you are slowly building a pile over time, remember that much of the moisture can evaporate from the top foot of the pile, so re-wet the top of the pile as you build it. If a pile seems too wet, turn it to aerate and add some bulky dry materials.

A simple homemade compost bin

There are also several organic "compost activators" on the market that help speed up decomposition. Compost Alive! Activator available from Gardens Alive (www.gardensalive.com) is effective and inexpensive.

Prior to winter, cover compost with a thick layer of straw and a weighted plastic tarp to provide insulation, help retain moisture and shield the pile from our drying winds. Also, you do not want snow to interfere with turning or become mixed in with the compost, so completely tarping the pile and clearing the top and perimeter away after each snowfall is a must.

It's advised to turn the pile about three weeks to one month after initial construction. At this point, oxygen becomes the limited element and the pile cools down. Turn the pile with a pitchfork by moving the material at the center of the pile to the outside and working the material on the outside to the center. When turned, the pile can then reheat with a new surge of microbial activity. A properly built pile can reach internal temperatures from 140° to 160° F.

With the proper carbon/nitrogen ratio and regular turning, heat will continue to be generated and decomposition will occur all year. Even during cold winters, the composting process will continue at very low levels if a pile is large enough and well insulated. But during winter, turning should not be done as often as in warm weather, as there will be a longer temperature recovery period after each turn when the colder exterior of the pile is turned into the interior.

Shielding the pile from cold winter winds will also help prevent temperature loss. Thoroughly wetting the exterior of the pile, particularly on the north windward side, will reduce wind penetration and permit the interior heat to extend closer to the surface of the pile. The pile will not become anaerobic or create an odor nuisance during really cold weather if it is not turned.

Rain usually does not seriously affect composting if the piles are finished with a rounded top so rainwater can run off and if the compost piles or bins are adequately drained so that water does not stand around or penetrate the piles. Turning should not be done in the rain, as the pile may become waterlogged.

Compost maturation depends on (a) the number of times a pile is turned, (b) the particle size of the compost materials, and (c) the climate and the season. An average-sized well-balanced compost pile built in Pagosa can take four to six months of warm weather to mature, and wintered-over piles can take well over eight months. The more times a pile is turned, the faster it will decompose. Those who use composting drums tell me it is fastest type of composting available, producing rich, uniform compost in weeks, not months, again, depending on the mix of materials, moisture of the compost, weather, etc.

The finished product

Finished compost is dark in color and has an earthy, sweet smell. It may not look like the finely textured product sold at the garden center. Small sticks and other materials that haven't thoroughly composted will continue to decompose in the soil. There is no need to sift compost that is going into a garden bed. However, if used as an ingredient for potting soil or seed sowing mix, always use your most finished, stable compost that has been sifted through 1/4-inch wire screen to remove larger particles. 

Right before it's time to plant, turn under a two-inch layer or more of compost into the top foot of depth of the garden bed. In established beds, turn under 1/2 to one inch before planting each spring. Sprinkle in a handful or two of compost in holes when planting annuals, and mix in more when planting perennials. Compost is also excellent used as mulch around trees, shrubs, and as a top dressing around other established garden plantings.

Return to Gardening & Landscaping Home Page

Top of Page