Gardeners and compost enthusiasts use a wide variety of organic materials when constructing their compost heaps, including hay and leaves. According to Deborah Martin, co-author of "The Rodale Book of Composting," dead leaves provide an ideal carbon-rich material for your compost. However, unless you're using freshly cut, green hay straight from the field, you'll need to supplement your compost heap with additional nitrogen-rich organic waste to give the decomposing bacteria in your pile adequate nutrients for quick composting.
Gather your hay and leaves, as well as other moist, fresh nitrogen-rich organic waste materials such as cow manure or green grass clippings. Aim for approximately 1/3 of the volume of your compost heap to come from each of the three main ingredients. For example, for every wheelbarrow full of leaves that you have, plan on collecting a second wheelbarrow full of hay and a third wheelbarrow full of high-nitrogen organic waste.
Prepare your leaf waste by shredding and tearing it into smaller pieces to make it easier to handle and quicker to decompose. Run the leaves through a leaf shredder or run over them with a push mower to chop them into adequately sized waste pieces for your compost heap.
Sprinkle a 2- to 3-inch layer of shredded leaf waste across a 3-foot-by-3-foot area of plain topsoil. Pull apart your hay and drop it in a loosely packed 2- to 3-inch layer atop the leaf waste. Spread a 2- to 3-inch layer of nitrogen-rich waste on top of the sprinkled hay. Scoop several handfuls of plain topsoil over the nitrogen waste to help jump-start the microbial activity in your compost heap.
Spray the layers of organic waste with your garden hose to moisten it. Use enough water to make the composting materials about as damp as a wrung-out sponge. Add additional 2- to 3-inch layers of the leaves, hay and nitrogen-rich waste, alternating the three layer materials until your compost heap measures minimally 3 feet tall.
Leave your compost heap alone for two to three weeks to allow the composting microorganisms enough time to begin their decomposing activity. Turn the pile once weekly thereafter with a manure fork or garden rake, shifting the waste in the center of the pile to the edges and the materials from the edges to the center of the heap. Monitor the moisture level when you mix the layers; compress a handful of the damp materials to ensure that you can squeeze out one to two drops of liquid, which, according to the University of Illinois Cooperative Extension, indicates the correct compost moisture levels. Continue these maintenance procedures for four to six months or until your compost becomes brown and crumbly and has a mild, earthy odor.