Organic compost is easy to make from lawn trimmings, fallen leaves, animal manure, kitchen scraps and other organic waste. Build a compost pile by alternating layers of fresh, green plant materials with layers of dried, brown material. Water and cover the pile with a tarp, and in several months you'll have free organic fertilizer to feed your plants.
Garden-supply stores sell ready-made organic compost and manure in bags. You can also purchase organic fertilizers like bone meal, seaweed extract and fish fertilizer in granular or liquid form.
Visit stables and zoos, where you can purchase or collect animal manure for composting. Zoos sometimes sell their composted animal manure in bags. Always get permission before collecting animal manure at stables.