Mixing it Up in Your Backyard: Composting 101

To compost or not to compost—it’s really not a tough question to answer; in fact, it’s a no-brainer. Just toss your food out your back door instead of into your garbage and you are composting! OK, so it may be more sophisticated than that, but not much. You may have heard of the need to layer your compost a certain way, and then water it so much, and turn it every so many weeks, and occasionally read it a bedtime story. And what’s great about this recipe is that within 4 to 8 weeks, you should have moist, black, sweet-smelling mulch which you can use to feed your garden, your lawn and your potted plants. However, what you may not know is there are two types of compost piles. There’s what’s called a “Hot Compost Pile” and a “Passive Compost Pile.” The beauty of a passive recipe is that you don’t have to regularly do anything in order for the process to take place, except to toss egg shells, grass clippings and coffee grounds onto the pile. “The composting process will still happen,” said Anne Murphy, education coordinator for Spokane Regional Solid Waste Systems. “It’ll just take a year or more to produce the desired mulch.” This is exciting news for many, I’m sure, and rotting food is not usually something to get excited about. Now the lesser motivated recyclers and gardening-inclined among us can also save on garbage bills and synthetic fertilizers, while saving disposal space and protecting the aquifer like the more motivated composters have been doing for years. So once you start the process of composting, you might find that it can be a little addicting. Although there’s no white lab coat and look-of-a-crazed-scientist requirement, it’s about as good as science gets—seeing your onion skins, tea bags, and vacuum cleaner lint turn into stuff you can pay up to $20 for? Priceless. So in case you find yourself a little more inclined to tend to your compost pile than you thought, there are some things you should know. A good place to start, and a spot to pick up a free compost bin (Spokane County residents only; 1 per household; please bring I.D.) is the composting fair at the John A. Finch Arboretum on Saturday, April 24, 11 a.m.-2 p.m. Participants visit compost stations to demonstrate how to care for a “Hot Compost Pile” and how the process takes place. All participants must be registered by 1:30 p.m. to complete all stations as it takes approximately 45 minutes to complete. The event, sponsored by master composter volunteers of the Spokane Regional Solid Waste System, is free and open to all, and has been an annual event since 1996. Since then, 7,660 compost bins have been distributed. “Assuming that half of those bins are still in use today could mean approximately 416 tons of food waste is being diverted annually from the landfills,” said Murphy. That’s roughly 2,500 pounds of food waste that your household could divert each year alone. However, if you’re not able to make the event, you can make your own compost bin using wood and/or wire mesh or select from a variety of manufactured bins, in a wide price range. It doesn’t really matter which bin you use, as long as it’s big enough—too small and the pile won’t “heat up” (decompose efficiently), but also, too large, and it can become anaerobic (insufficient oxygen slows down the process) and smell bad. For optimum composting results, aim for your bin dimensions to be between 3’x3’x3’ and 4’x4’x4’. The insects and microorganisms (bacteria, yeasts and fungi) that do the work of composting will come no matter what you do. A number of macro-organisms, like springtails, ants and fruit flies also contribute to the process. Fortunately, putting out the right ratio of materials—roughly 30 parts carbon to 1 part nitrogen—will be like offering them a free all-you-can-eat buffet. So just when should one dig into such a task? “Now is a good time,” Murphy said. “People often think about starting compost bins in the spring as thoughts turn to gardening.” However, she says planning is important, as dried, brown leaves from the fall are an important part of the mix. This “mix” must have four equally important elements. Carbon: High carbon materials tend to be brown and dry, like dead grass clippings, leaves, and even shredded cardboard and manure from herbivores. Carbon provides the “energy” or “heat” via microbial oxidation, facilitating the decomposing process. Nitrogen: High nitrogen materials tend to be green (or colorful, like fruits and vegetables) and wet. These can be fruit peels, green grass and garden clippings (avoid weeds, weed seeds, dairy and meats) and are necessary to grow and reproduce more organisms to oxidize the carbon. Oxygen: Oxygen is also needed to oxidize the carbon, and is introduced by turning the compost (a pitchfork works best) about once a week. Water: Water in the right amounts is needed to maintain activity, but should only be necessary during dry spells. If you have built a “Hot Pile”— a compost pile with a good carbon to nitrogen ratio, and one that’s sufficiently damp and oxygenated, the composting process should start immediately, and you should be rewarded with rich, moist compost within 4 to 8 weeks. Whatever your approach to composting, one thing is for sure: you’ll feel better about reducing waste and at the same time, feeding your backyard with the rich nutrients it needs.