It’s that time of year again when leaves begin to fall from the trees and shrubs, summer annual weeds like crabgrass and spotted spurge begin to die and the temperatures begin to cool off.
A light scattering of leaves won’t harm a lawn, but excessive cover of several inches prevents sunlight from reaching it. The leaves seem to “glue” together as they get wet from rain and are on the lawn for an extended period of time. This will prevent the grass plants from making carbohydrates that are needed to carry it through the winter.
Raking leaves used to be such a laborious task. It also became expensive as many municipalities started to require that all yard waste be put into paper bags with a sticker. These stickers cost upwards of 3 or more dollars each. It is not uncommon to see twenty or more of these bags lined up in front of someone’s home on garbage day…
There are options for fallen leaves other than bagging them up and putting them out for the trash collector.
Composting is a great way to handle the leaf cover. Most lawn mowers are of the mulching variety and do a great job shredding up the leaves. It is important to stay ahead of the dropping of the leaves and don’t let them get too thick. It will still work, but it will take a much longer time. It may even require you to go back and forth across the same area several times.
Some people may think that mulching the leaves will add to the thatch layer. Research at Michigan State University used a mulching mower to shred up to about one pound of leaves per square yard of lawn (one pound is equal to approximately 6 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.).
Go ahead and mow leaves if you have a cool-season lawn, it makes sense to be on a fall nitrogen fertilization program and core-aerate in the fall. If you have a warm-season lawn, you can still use this technique but wait to fertilize and core-aerate until the following late May or early June. For information on fall core aeration contact your local Spring-Green.