Composting Fall Leaves

Fall leaves are a valuable resource to gardeners to keep their gardens and soil in prime productivity. Here are a few pointers to optimize fall leaf composting.

• Use large compost bins, 5 to 6 feet across. This large size allows for rapid internal heating of the compost pile, which drives the decomposing process. Smaller bins will be slow to heat and will not be able to maintain processing temperatures through the cold Minnesota winter. Bins larger than 6 feet across may restrict oxygen infiltration into the leaf pile, slowing decomposition.
• Shred leaves with a lawn mower or leaf grinder. Shredded leaves compost faster.
• Mix some nitrogen into the leaves as you add them to the pile. Leaves are high in carbon, which makes for great compost, but are comparatively low in nitrogen needed to feed the decomposing bacteria. This could be added as a nitrogen fertilizer or fresh green organic matter. For example, add 1-2 cups of bone meal or cotton seed meal per wheelbarrow of leaves. Or add 4 part leaves with 1 part fresh grass clippings or similar green garden debris.
• Moisten the leaves as they are piled. Rains will be slow to wet through a leaf pile, and moisture is essential for decomposition.
• Do not turn compost piles in the fall. This allows valuable heat to escape, which is needed to drive the process through the cold Minnesota winter. However, compost piles should be turned in the spring, every 3-4 weeks thereafter, in order to speed the decomposing process.

With attention given to these composting needs, a gardener can produce fall leaf compost ready to use by the following late spring or sooner. On its own, a pile of leaves may take 2 to 3 years to decompose.