How to Compost Leaves

Phyllis Heuerman
Frederick County Master Gardener Program

Leaves are often referred to as "Gardeners' Gold". Their bright green appearance in the Spring is a harbinger of the beginning of a new life cycle. Their presence in the summer provides much needed shelter from heat and rain for wildlife and humans alike, as well as being the vehicle through which trees produce their own food. Their dramatic beauty in the Fall can be unparalleled. In addition to all of this, properly used as mulch or compost they provide outstanding organic matter and nutrients to the soil.

Unfortunately, to use leaves effectively as mulch and compost they still must be raked or blown from your gardens and lawn so that you have control over where they are used. Leaving a thick layer of leaves on your lawn or garden can create conditions that lead to rotting of the grass or perennials beneath. So, to start with rake the leaves up into a pile.

Once your leaves have been gathered, you have a choice between using them undecomposed, as mulch, or composting them before you put then in your garden. Regardless of how you are going to use them, the first step is to chop or shred your leaves. This will save space if you are placing them in a bin, it will minimize their blowing around and matting if you are placing them in the garden, and it will hasten their eventual decomposition into composted organic matter.

If you do not have a shredder, and do not wish to rent one, you can use your lawn mower to shred the leaves. If the leaves are on your lawn attach a bagger to your lawn mower before you begin cutting. As you cut the lawn, the leaves will be shredded and gathered into the bagger. You may also gather leaves in a pile and run the lawn mower without a bagger through the pile. Direct the discharge shoot in one direction at all times so that the shredded leaves are placed in a pile and not blown all over the place.

Once you have your shredded leaves, you may place them in your garden as mulch immediately, if you wish. However, do not place an excessive layer of mulch directly on the crowns of herbaceous perennial flowers. This is not necessary, and it can lead to root rot. If you are trying to extend the season for winter root vegetables, like rutabagas, carrots, leeks, kale or beets, you may use a heavy layer of shredded leaves to cover them. You may find that you can harvest these vegetables all winter with this added protection from the leaves. If you do use uncomposted shredded leaves as mulch in your garden, you should add some slow release nitrogen fertilizer to the garden in the Spring, as the process of leaf decomposition may rob the soil of nitrogen.

Another alternative for your shredded leaves is to compost them, either alone or with other organic matter. The simplest but longest process is to place the shredded leaves in a wire bin. Leave them there for two years, turning them occasionally, and you will have a really nice product. Leaf mold is a special fungus-rich compost that can retain three to five times its weight in water, rivaling peat moss. The "Leaf-Gro" that is available in most of or local garden centers is leaf compost. The only disadvantage of using leaves alone for composting is you will find that you need a tremendous amount of leaves to produce any quantity of compost.

Leaves can be used more effectively as a component in a compost pile that contains a variety of organic matters. A good balanced compost pile contains materials rich in nitrogen and others rich in carbon. Leaves can provide the carbon component of your pile. Other good carbon components include straw, nonglossy paper, wood and bark chips. Good nitrogenous materials include grass and plant clippings, uncooked fruit and vegetable scraps, eggshells, and coffee grounds. Use your shredded leaves and other carbon materials to layer between your nitrogenous materials in a bin. Turn the pile occasionally to aerate it, and make sure that it is moist, but not soggy. It is not necessary to add commercial compost starters or fertilizer to a compost pile to start it "cooking" but doing so may hasten the process. The amount of time it will take to produce compost depends upon its size, composition and conditions. The process can take anywhere from three months to one year. My small suburban compost bins take 6 to 9 months to produce a fully composted product. I cut the materials I am placing in the piles into small pieces, and I turn the piles about once every 3 to 4 weeks.

I find reusing organic materials such as leaves for mulch and compost to be one of the most satisfying aspects of my gardening. I hope you will give it a try.

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