A compost heap needs two kinds of material: green waste such as vegetable peelings, fruit cores and coffee grounds, and brown waste such as dry leaves, cardboard and straw. Aim for roughly one part green to two parts brown. Turn the heap with a fork every two to three weeks to let air in. A healthy heap feels as damp as a wrung-out sponge and smells earthy, not sour. Leave out meat, dairy and cooked food, which attract rats. After six to twelve months the compost is dark and crumbly and ready to dig into flower beds.
