Finding your inner compost guru


What does a compost bin look like, anyway? What about a worm-compost bin?

In the nearly 25 years I have been teaching people how to compost, I have seen as many ways to compost as ways to eat green chile. The thing is, most of those methods, when employed here in our dry New Mexico air, rarely work. In general, the compost piles I see are more effective rodent bed-and-breakfasts than an efficient way to recycle food scraps or yard wastes. My passion has become helping as many people as possible find the art, the way to their own inner compost guru.

The first and most critical step is understanding how to manage moisture. In our dry, high-altitude air, encouraging airflow through a compost pile is a terrific way to dry it out. Dry food scraps are well-preserved food scraps. In other words, the compost process halts when moisture is absent!

Unfortunately, many well-meaning composters get sidetracked making bins with materials that encourage the drying process. Compost tumblers are as efficient at drying compost as clothes dryers are at drying clothes. Other popular choices for bins that wind up being great compost dryers include bins made of pallets, wire, fencing or piles made without any bin at all. What to do?

The aim is to keep the air out – mostly. Yes, reduce the airflow to a minimum and let the water stay in the bin. Build a bin out of solid wood or straw bales with no venting at all. Wood and straw breathe just enough. Better still, they bring worms to the process, especially red worms. Unlike bacteria, red worms move through the bin to get to the air they need. In doing so, they help bring air to immobile bacteria. Using worms in a bin with solid walls uses the least water of any method I know of and has the added benefit – huge in my opinion – of eliminating the need to “turn” or aerate the pile. Water is heavy. Compost is heavy when watered. Turning a pile to aerate it is one thing few people take the time and effort to do. Worms in a pile do this work for us!

Do worms survive the winter in an outdoor bin? Mine have in Santa Fe for 20 years without skipping a beat. I have met folks from Canada, Wyoming, New York and Michigan who compost outdoors with red worms. In my experience, it is easier to keep worms happy in an outdoor bin than one kept indoors. An outdoor bin has the advantage of being nearly a red worm’s natural habitat. A small plastic tub under your kitchen sink is not even close. There are many advantages to having the bin outside. How does not breeding flies in your house sound?

Interested in learning more? Come to a workshop on Sunday (April 23) at the Taos County Agricultural Center in Taos, when I will discuss all aspects of composting with red worms, as well as how to get the worms to live in your garden beds.

McCarthy has been raising and selling red worms and worm castings in Santa Fe for more than 20 years.