Don't Let Leaves Smother the Turf

Don't Let Leaves Smother the Turf


Leaves. Useful to the tree. Great for jumping in. Not much fun to clean up. Find out what you should be doing with those fallen leaves to let them help you and your landscape in the long run.

Once the leaves fall to the ground, they can become a big headache. It may seem tempting to let all the leaves fall off of the trees then try to pick them up all at once, but this isn’t the best practice. If the leaves get too deep on top of the turf, they can actually smother the lawn. Rake and remove, or mow leaves on a regular basis to avoid a build-up on lawns which can suffocate turf and increase the risk of snow mold disease.

Leaves have many uses in the landscape. They make good mulch in landscape beds and good winter protection for tender perennials. Covering the bare soil with ground-up leaves will help prevent winter annual weeds from germinating and add organic matter for the soil as they decompose. Finer pieces of leaves can be added to the compost bin, worked into the garden, or allowed to infiltrate into the lawn. Avoid using leaves from the black walnut tree in compost bins or garden areas. They contain a compound called juglone that inhibits the growth of some garden crops.

Remove leaves the easy way, let the lawnmower do the work for you. Pulverize leaves by using a mulching mower or making 2-3 passes with a regular mower. After mowing, the pulverized leaves should not sit on top and cover the turf, but rather filter down into the grass. Up to 6” of leaves can be mulched at a time, depending on the type of mower that you have. Push mowers will handle smaller amounts of leaves but are still very effective. Consider alternating between bagging and mulching leaves, especially if you have a lot of leaves that collect.

Along with getting the leaves off the turf surface, mulching them into the lawn has additional benefits. Research has shown that there are several benefits to mulching leaves into the turf. In years that followed the mulching of leaves, turf spring green up can be achieved with less fertilizer. There can also be fewer weeds because the decomposing pieces of leaves cover up the bare spots between turf plants where weed seeds normally germinate. Michigan State University research has shown nearly a 100% decrease in dandelions and crabgrass germination following the adoption of mulching leaves into the turf after just 3 years.

Another use for the fallen leaves takes a little planning. Leaves can also be saved for the following year. When dry, leaves can be saved in plastic bags to use as a source of carbon in next years’ compost pile. In a good compost pile, there should be equal parts of carbon, brown plant material, and nitrogen, green plant material. Often during the growing season, only high nitrogen plant material is available. By saving your fall leaves now, you can help to ensure the proper carbon to nitrogen ratio for your compost pile. The leaves will decompose more quickly if they are chopped or mulched into smaller pieces, but it is not required before you put them into the compost pile. Make sure that the leaves you are using in the compost pile are not diseased as most home compost piles are not able to reach proper temperatures to kill many of the pathogens.

Water pollution is another potential problem with tree leaves. Leaves that wash into streams, lakes, and ponds can contribute to water pollution. If an abundance of leaves is allowed to decompose in the water, this can lead to impaired water ecology, commonly seen as excess algal growth. To reduce the pollutant load on surface water, do not dump tree leaves or grass clippings along stream banks or near ponds where rainfall and snow melt can carry them into the water. Also remember to remove fallen leaves from streets, driveways, and gutters to prevent them from washing into storm drains.

Rake them. Mulch them. Compost them. Let leaves work for you.

This article was reviewed by Nicole Stoner

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