By David G. Hallauer
Kansas State University Research and Extension
This past week’s cold weather was the last straw for most tree leaves, I’m afraid. That means they are about to end up in your gutter as well as covering your turf.
While a few leaves won’t hurt turf, the excessive drop from some trees in the fall, combined with the extended period they cover the turf, can cause some issues. The problem: the grass can’t produce the carbohydates needed to carry it through the winter. Fortunately, we have numerous options for disposal, even above the typical bagging them up and hauling them away or even composting.
One option is direct incorporation into the garden or flower bed. Start by using a lawn mower with a bagging attachment to chop and collect the leaves. Transport them to the garden or bed and apply a two to three inch layer of leaves on the surface of the soil. Till them in (if soil conditions are appropriately dry), then repeat every couple of weeks until you run out of leaves or the weather becomes too cold.
You can also mow with a mulching mower and let shredded leaves filter into the turf canopy (side-discharge mowers won’t shred the leaves as thoroughly.) This method will be most effective if you do it often enough that leaf litter doesn’t become too thick. Mow while you can still see grass peeking through the leaves. It can work really well, even with a lot of leaves. Research at Michigan State University tested the use of a mulching mower to shred up to about one pound of leaves per square yard of lawn (approximately six inches of leaves piled on the grass) for five consecutive years. They found no long-term effects of the shredded leaves on turf quality, thatch thickness, organic content of the thatch, or soil test results (pH, nutrients, etc.). If you mow leaves and have a cool-season lawn, it makes sense to be on a fall nitrogen fertilization program and core-aerate in the fall—things you should be doing anyway.