Amending Soils With Leaves

Purpose

• Soil is amended to improve its ability to retain and distribute water, nutrients and air; all of which are essential for plants to thrive. Leaves make a good soil amendment because collecting leaves is an inexpensive activity that many landowners already perform in the normal course of maintaining their property. Leaves are a renewable resource. Leaves do not require additional components to help them decompose, but the final product may benefit from additional nitrogen.

Preparation

• Collect the leaves in the fall. Shred the leaves, using either a mulching lawn mower or dedicated leaf shredder, to create more surface area to hasten the breakdown. Wet the leaves down, and stack them in heaps in an out of the way section of your property. Construct a cage from chicken wire to keep the piles in tact or place them in large, plastic bags that you puncture for drainage and air circulation. Turn the leaves if the temperature of the pile reaches 150 degrees or if it begins to emit an odor. Odor indicates anaerobic decomposition. Turn the pile to introduce oxygen to restart aerobic decomposition.

Incorporation

• Spread 1 to 2 inches of leaf mold over your planting bed, and mix it in to the soil at a depth of 6 to 8 inches. Plants derive the most benefit and sustain the least harm from leaves that have fully decomposed. Avoid incorporating the leaves into the soil before they are fully decomposed because the fungi and bacteria that are consuming the leaves will also consume nitrogen that your plants need.

Timing

• Typically, leaves need at least two years to break down sufficiently to use as a soil conditioner. Several factors contribute to the leaves’ rate of decomposition, including temperature, surface area, type of leaf, moisture levels, oxygen levels, size of the pile and the frequency at which you turn the pile. Create a permanent place for your leaves to maintain a continuous supply of leaf mold for your soil.