Do Leaves That Fall from Your Trees Make Good Fertilizer?

Preparation

• Shred or chop fallen leaves before you use them as fertilizer or compost. Whole leaves break down slowly and may become matted and smother the garden. The University of Delaware Cooperative Extension recommends placing a bag attachment on your mower and mowing the leaves. For easier shredding, wait until the leaves have dried.

Application

• Before planting, work the shredded leaves into the soil. The leaf fragments will add minerals and improve drainage in the soil. You can also make compost from your leaves. Add grass clippings, cow manure or commercially produced nitrogen fertilizer to the pile of leaves as a nitrogen source for beneficial microorganisms. To provide microorganisms, the Purdue University Extension recommends adding soil and lightly watering the pile. Turn the leaves frequently to promote faster decomposition.

Time Frame

• According to the Missouri Department of Conservation, you should dump bagged leaves and allow them to decompose for nine months before adding them to soil. You can add shredded leaves to planting beds or compost heaps in the fall, or add rotted leaves or compost to garden soil the following spring. Decomposing oak and maple leaves release phenols, which suppress plant growth. Do not add fertilizer containing these types of leaves until after seedlings have established.

Benefits

• Autumn leaves are a low- or no-cost alternative to commercially produced fertilizers. When you use leaves as fertilizer, you help prevent the harmful runoff caused by chemical fertilizers. Recycling is a safer method of leaf disposal than burning, and more convenient than attempting to dispose of bagged leaves. Organic matter in soil improves the soil's ability to absorb water and adds beneficial, nutrient-enhancing organisms to depleted soil.