Compost occurs in a natural process when helpful soil bacteria break down dead organic matter into soil rich in nutrients and organic material. Although most gardeners begin a compost pile by adding materials as they become available, establishing a large compost pile may achieve faster results. Large piles, however, also require greater vigilance and more maintenance.
Hot composting occurs when nutrients and conditions in your compost pile are optimal for promoting bacterial reproduction and productivity. While hot composting produces finished compost in as little as eight weeks, getting those conditions just right can be a challenge. Hot compost piles must generally be taller than regular compost piles so that the core of the pile can achieve the proper temperatures. "Rodale's Ultimate Encyclopedia of Organic Gardening" recommends building a hot compost pile that is at least 3 feet in every dimension, although they also caution that productivity in piles that are too high may slow because of a lack of aeration.
The bacteria that turn your kitchen scraps and yard wastes into fertile soil require air to live. This is the rationale behind turning compost: using a garden fork to exchange the stuff inside the pile with the material on the outside. Although compost expert Barbara Pleasant debunks the notion that composting requires frequent turning to work, pointing out that compost is a natural process that will occur with or without human help, productivity may stall in larger piles because air cannot reach the bacteria at the center. Frequent turning is, of course, an option, but "Rodale's Ultimate Encyclopedia of Organic Gardening" also recommends the labor-saving techniques of inserting sticks or stems, like sunflower stalks, into the pile while building it or perforating it with a crowbar or garden fork.
Your compost pile also requires the correct moisture level, and too much or too little moisture can cause problems or slow productivity. Larger piles may become dry or hold too much moisture at their centers. Over-wet compost piles stink and cut off the supply of oxygen to the helpful bacteria doing all of the work, and over-dry piles lack the water the bacteria need to move from place to place. If you see ants starting to nest in your pile, it's too dry. Turning a large compost pile will allow you to check the moisture levels inside the pile while also helping to achieve a better balance by distributing wet materials in with the dry. If your compost is too dry, add water and materials like straw or grass clippings that help retain the water. Toss in some paper scraps or other dry materials if the pile is too wet.