Compost converts waste material into a fertilizer. Bins should be almost 30 cubic feet to ensure it retains enough heat to spur composting. Choose a location for your bin that is partially shaded. A pile can contain leaves, grass clippings, prunings, straw, spoiled hay, coffee grounds, eggshells, paper and wood ash. Remember you should add equal parts of green material (nitrogen) like fresh grass clippings and food scraps to one part brown (carbon) such as leaves. Keep it as wet as a wrung-out sponge and aerate your pile by stirring it once a week. You can layer in manure, garden soil and commercial fertilizer to speed bacterial action. You should have finished compost in about three months.