So what do you do with your leaves in the fall? It turns out that mulching them and returning them to the lawn offers many benefits. If there is an abundance, you should use them as mulch for gardens and planting beds or as filler for your compost pile. Don't put them on the curb - especially if they landfill-bound. Leaves are free organic matter and should be used on the property they came from when possible.
How to Mulch Leaves
I strongly encourage mulching grass clippings with a mulching mower, and I recommend the same type of mower for leaves. A mulching mower uses unique mowing blades in conjunction with "baffling" under the deck. The leaves or grass clippings are cut multiple times as they circulate in the interior chamber. The finely chopped material eventually gets pushed down onto the lawn surface. Occasionally, leaves will have to be mowed several times. It may seem a little tedious, but it is far more cost-effective and labor-saving than alternatives like raking or leaf blowing.
Benefits of Mulching Leaves
A study by Michigan State University indicates that mulching is 100% beneficial for the lawn. Mulched leaves are decomposed by earthworms and microorganisms and turned into plant-usable organic matter. Mulched leaves are better for the greater community, too, because they stay on site and out of landfills.
Oak leaves and maple leaves were mulched and redistributed through test lawns and found to have a negligible or beneficial effect on turf quality and color. They had no negative effects. Mulched sugar maple leaves even appeared to inhibit broadleaf weeds such as dandelions.
Even Oak Leaves?
Yes, even oak leaves.
Oak leaves seem to be surrounded by myth and misinformation when it comes to their role in mulch. While it is true that they seem to take forever to fall from the tree, and the leaves themselves are rigid and tough to mulch, the mulched oak leaf is not acidic. I repeat, mulched oak leaves will not turn your soil acidic, and they are perfectly acceptable as a lawn mulch. I have found no evidence, experience, or scientific proof supporting the notion that oak leaves are bad for the lawn. Quite the opposite actually. The Michigan State study indicates that there was no change in soil pH after six seasons of mulching oak leaves into a lawn.
Stay on a Lawn Care Program
Many people who share negative views on mulching leaves in the fall have stories about their lawns being smothered or grass becoming weak and thin. It is true that matted layers of unmulched leaves have negative effects.
If mulching is done correctly and lawn performance is still poor, there may be another factor. Soil microbial life may be lacking. Mulched leaves are an amendment for the soil, not a replacement for fertilizer. Fertility still needs to be maintained with fertilizer applications. The microbes in healthy soil assist in the breakdown process and to avoid a matted layer of mulch.
Tips for Successful Leaf Mulching
Do not mulch to the point where the leaves cover and smother the grass. The grass blades should be vertical and visible through the layer of mulched leaves. In certain areas, it may help to spread the mulch around from thick spots to areas with thinner mulch distribution.
If there is an overwhelming abundance of leaves, use some in flower beds, gardens, or a compost pile. The lawn is only one area that can benefit from mulched leaf material. The overall goal should be to avoid raking, leaf blowing, collecting, handling, and disposing of leaves off-site.
Updated by Kathleen Connolly, 11/1/2015