By Debbie Roland, Master Gardener, Compost Specialist
So, what is composting and what’s the big deal? All composting works on the concept that organic waste (anything that comes from plants or animals that is biodegradable.) will break down into a rich natural soil amendment if the conditions are right. Composting is the same wherever you live, but different rules are suggested for desert composting. It’s a challenge to compost with high winds, intense sun and low humidity so the old rules have been tweaked to better ensure success.
Your ideal bin should be a 3’ square that is open on the top and bottom. Use a bin with solid sides so that you can better manage the airflow to decrease evaporation. If you already have a bin with too much air flow, you will need to line the inside with a plastic material or cardboard, leaving about a one inch air space at the bottom of the bin. Start with 6-8” of large twigs or sticks on the bottom of the pile placed directly on the soil. These are your bulking materials and decompose slowly so they maintain air space. They also resist compression from the weight of the materials above
Next, alternate green and brown very damp materials in about 6” layers all the way to the top of the bin. Greens provide nitrogen and consist of coffee grounds, egg shells, fruit and vegetable scraps, garden waste, grass clippings, hay, and manures (no dog or cat). Browns provide carbon and include leaves, shredded paper, cardboard, bark, peat moss, pine needles, sawdust and straw. Soak any dry material before adding. For example, dry leaves will absorb water if soaked in a pail or wheelbarrow.
Remember, the smaller the pieces the faster they will compost. If at all possible, it is best to compost in shade. The bin must be placed on soil, not concrete or asphalt as they heat up and increase the evaporation of the pile. A cover should be placed directly onto the materials in the bin to decrease loss of moisture. Use plastic, cardboard, a rug or carpet.
Since your compost materials will not always reach the top of the bin, a second cover (such as a tarp) should be draped over the entire bin itself.
Add water as necessary – probably two to three times per week. Yours may vary depending on the wind and the location of your pile, and you should adjust accordingly. Two weeks after you finish building the pile you should start turning it every week or two if you wish to speed up the Depending on conditions, your compost should be finished in six to eighteen months. It is best to sifting your compost before applying it. The leftover bulking material should be reused for your next batch of compost.
Remember, there are no composting police and, over time, you will develop your own recipe. More detailed information is available at nmcomposters.org.