Why Compost?

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A rich, pulverized compost delivers the organic matter and nutrients your plants need to thrive. Home composting is the most environmentally-friendly way of dealing with kitchen and garden waste, plus it produces compost that can be used as an excellent soil improver.

Homemade compost is a great match for all gardens, except the very smallest, and it is very easy to do. Only in the very smallest gardens will it be difficult to find space for a compost heap and material to fill it. Owners of such small spaces could consider worm composting to recycle food scraps and other organic material into a valuable soil amendment called vermicompost. Composting can be done all year however late summer to early winter is the peak time for making compost.

Getting The Right Balance of Composting Materials

Aim for between 25 and 50 percent soft green materials such as grass clippings, annual weeds leaves (no weed seeds PLEASE!), vegetable kitchen waste, or manure to feed the micro-organisms (bacteria and fungi) that are your demolition crew. The greens will provide the nitrogen pieces needed.

The remainder should be woody brown material such as prunings, wood chippings, sawdust, paper, cardboard, straw or dead leaves. The smaller the pieces are the faster they will break down. The brown pieces provide the carbon pieces needed.

The micro-organisms that produce the compost function best when the balance of green and brown materials is correct. It’s called the Carbon (C) to Nitrogen (N) Ratio. The best C:N ratio is from 25:1 to 35:1. Different leaf types have different ratios, so review the table in NCSU publication (1) below to find out what to mix and match from the materials you have on hand.

Turning the compost pile adds the air necessary for decomposition to occur. If the pile is too wet or becomes compacted, then the composting process is slower. Ideally, place a lot of composting materials on the pile at one time, and turn it periodically (perhaps every month) to introduce air. However, many gardeners are unable to fill the compost pile at once because they accumulate waste gradually. So manage your expectations to reality.

Remember:  Balance in all things:  You don’t want any single material dominate the pile. Kitchen waste and grass clippings are best mixed with brown woody material for needed air spaces & nutrient support. You can purchase products called compost accelerators, starters or activators. These are added to the pile to make “better, faster” compost. If you have enough of the basic recipe: green and brown materials, moisture and air, you won’t need these products for a rich, fertile soil amendment to mix into the garden.

Garden compost can take between six months and two years to reach maturity. Mature compost will be dark brown, with a crumbly soil-like texture and a smell resembling damp woodland. This is a process, not a pre-packaged product. It is unlikely that all the material in the pile will be like this, but any remaining un-rotted material can be added to the next batch of composting materials. Similar to the process of making sour-dough bread – you benefit from a starter piece that fermentation has already begun working on.

Keep It Organized

To Bin or Not to Bin, that is the question. Well it’s one question. There are more, such as open bins, closed bins, tumbling bins, anaerobic bins, homemade, or top of the line motor driven, steel bins. Or no bins. There are pros and cons to every option. Bins retain some warmth and moisture and make better compost more quickly, but even an open pile will compost eventually. Open bins made from wire or plastic mesh or wooden slats make quick compost in as little as six weeks, and given the right environment can get hot enough to kill weed seed (2). An earth base, with a covering of screening to keep out the moles, allows drainage and access to soil organisms. Closed bins are tidy, keep out both small two legged and four legged varmints, and produce a steady supply of compost if you regularly add to the ongoing ingredients. Tumbling bins make aeration a breeze. Turn the crank to rotate the drum, or in other models roll the giant ball around the yard. Anaerobic (without oxygen) bins are a bit more troublesome. Often permanent structures sunk into the ground, the microbes at work in these are a different type and produce a hydrogen sulfide byproduct that smells like rotten eggs. Whatever you choose, it is important that the site is not subjected to extremes of temperature and moisture, as the micro- organisms work best in constant conditions.

Bins less than 1 cubic yard in size are much less effective than larger ones as they hold less mass and produce less of an insulating effect to build up the heat and keep it in. Make sure you cover kitchen waste with garden waste after adding it to the pile and check that moisture levels are not too high, causing insufficient air in the pile. This will help your microbial and fungal workforce in getting the job done.

For more information, take a look at the following publications:

(1) http://content.ces.ncsu.edu/backyard-composting-of-yard-garden-and-food-discards

(2) http://articles.extension.org/pages/28585/composting-to-reduce-weed-seeds-and-plant-pathogens

Minda Daughtry is the Horticulture Agent for North Carolina Cooperative Extension in Lee County.