Compost is often called Gardener’s Gold, and rightly so. To a smart gardener, good compost is worth its weight in vegetables and then some.
What is Compost?
Compost comes in three basic forms: manure, compost, and mulch. All three of these have their advantages. Manure is the easiest to get and often the most practical, in terms of time, but is not always pleasant or socially acceptable. Compost is made by gardeners, usually, and is what we’ll be focusing on here. Mulch, of course, is slow-composting organic matter such as bark, wood chips, straw, and so forth that is most often used as a protective covering for compost or manure that’s been laid on the soil.
Composting is really just the utilization of nature’s natural process of breaking down dead plant material and turning it back into soil. With this comes a lot of nutrition, which boosts the soil’s ability to grow more plants. When a gardener composts, he or she is just speeding up the natural process through the knowledgeable manipulation of the factors that go into the breaking down of dead plant material.
These factors are: heat, nutrient mix, oxygen, and moisture. Heat is created by the bacteria and microbes as they break down the plant matter. The nutrient mix determines how active and healthy those microbes will be and how much they’ll have to “eat” while the oxygen level will determine how many microbes there will be. Finally, the moisture content will affect all of these things. All four elements working together create a micro-ecosystem that the gardener is attempting to optimize.
The main ingredients, or nutrients, a gardener is adding to the compost heap are carbon and nitrogen (C or N). Most agree that the optimum mixture is 25-30:1 carbon to nitrogen. So for every twenty-five or thirty pounds of carbon, you should be adding a pound of nitrogen. This is easily measured by the type of material you’re using. Some are a roughly even mix, such as grass clippings and sod, while others are weighted in either C or N’s direction. Shredded newspaper is mostly carbon, as are feathers and leaves. Dry manure and urine are heavy with nitrogen, as are coffee grounds.
Types of Composting
Compost Bins and Piles
Compost bins and piles are the two most popular ways of composting. They are roughly the same idea, though bins can definitely be a time-saver while piles can be almost unlimited in size. Both use the same principle of adding material to the “heap” (be it in a bin or a pile) and stirring it occasionally to keep it distributing so the central core of the compost heats up and does its magic.
Most compost bins or tumblers are built to have the compost contained and then stirred by either turning it over with a pitch fork or by turning the bin itself. Compost piles, similarly, are usually contained in some kind of enclosure, though they can be just heaped into a pile. These are also stirred, usually with a pitchfork. The stirring mixes the air, adding oxygen into the mix, and moves the processed material out and fresh carbon and nitrogen into the center. The middle of a compost pile can be 135-150 degrees Fahrenheit!
The hot process is a batch process that differs from the bin or pile methods in that it creates one big batch of compost (rather than a continuous trick of usable soil, as with other methods). This method requires more up-front work and planning, but is used by gardeners who want a large batch of compost at a specific time, say spring or fall, in order to prepare bare soil or rebuild a garden. While most often done in bins or large containers, it can also be done in piles.
A stockpile of compost ingredients is made, such as piles or bags of leaves, straw, grass clippings, etc. The hot process usually yields good compost in 2-3 weeks’ time (versus a whole season for piles and bins). Many gardeners have two or three bins they’re composting with in rotation, using the hot process with one bin while stockpiling in another, getting fresh compost weekly.
Layer composting is popular and is often used with the square, stationary bins sold in garden shops and stores. The home owner adds scraps and cuttings to the top of the bin and it slowly breaks them down, in layers, with fresh compost dirt coming out the bottom on a more or less continuous basis. These are the least labor-intensive of the composting methods, but are really only suitable for small-scale gardens (such as herb gardens, pot or bucket gardens, etc.) rather than for family-sized garden plots.
What Not to Compost
Anything organic can be composted. With that in mind, however, there are many things that are not well-suited to the home gardener’s compost bin or heap. Generally, waste from carnivores and omnivores (dogs, cats, humans, pigs) are not a good idea in a compost heap for health reasons. Most meats and meat-based fats should likewise not be composted.
Very thick and heavy vegetable matter (wood chips, cardboard, office paper, etc.) is also not a good idea in a compost heap unless you plan to allow a lot of time (possibly years) for it to break down.