Not an expert, just a gardener. Short answer: just letting leaves fall on your lawn for a period of time is unlikely to provide fertilization, in fact it may hu

Not an expert, just a gardener. Short answer: just letting leaves fall on your lawn for a period of time is unlikely to provide fertilization, in fact it may hurt your lawn, because the leaves will not break down fast enough and will instead cut off your lawn's access to air and sunlight. Long answer: You need to break down the organic matter in the leaves through composting. To speed up composting you want the right proportions of both brown (carbon - your leaves) and green (nitrogen) matter, the right moisture levels, and access to oxygen, usually in a large pile to create the perfect environment for the microorganisms that break down the matter. Your leaves are a great base for your compost, I always use mine, but you will probably need to put a little sweat equity into it, as well as kitchen scraps, lawn cuttings, etc. to get the right proportion of greens.