Every year, I look forward to when the trees in my yard turn beautiful shades of yellow, orange and red. But I know what’s next--a thick layer of leaves on my lawn that must be dealt with. Not exactly my idea of a fun autumn afternoon.
Luckily, a few years ago I started seeing reports from university turfgrass researchers stating that mowing over dried leaves on a lawn, then letting the small pieces fall to the soil surface, reduced common lawn weeds the following year. They found that chopping leaves into tiny bits caused them to create “mini-mulch” between grass plants that prevented weed seeds from germinating. As an added benefit, the leaves eventually broke down and add much-needed organic matter to the soil.
These reports inspired me to give it a try, especially because simply mowing over leaves seemed so much easier than raking, bagging and disposing of large piles. A standard power mower works fine; just remove the bag attachment. After trying it for a few years, here’s what I’ve learned:
- My lawn has fewer weeds. I don’t keep a strict count, but I’ve noticed fewer dandelions, purslane and spotted spurge plants in my grass. The effect is most impressive in spring and summer in the areas of my lawn where the grass is thinner. A few weeds have popped up later in summer, as the leaves have completely broken down by early fall. Nonetheless, it has certainly helped in the early part of the growing season.
- My grass seems healthier. Part of the benefit of mulching leaves is that they eventually break down and release organic matter to the soil. This benefits the grass because our soils are naturally low in organic matter. The higher the soil organic matter, the healthier roots will be.
- Mowing works if the leaves are dry. It’s important to mow over the leaves when they are crispy, which allows them to break into pieces small enough to fall to the soil surface. It may take more than one pass to get them small enough. If it rains or snows, the leaves get too soggy to break, so mow them soon after they fall.
- Don’t leave big clumps or thick mats of leaves. I was surprised that I was able to successfully mow a leaf layer as thick as six inches. But if you see clumps or mats of leaves after you mow over them a few times, rake them up and get them off your lawn. A thick layer of leaves will cause the grass to thin and may encourage snow mold.
- The leaves only prevent new weeds. If you have an existing weed problem, this method won’t solve your problem. It may, however, slow the rate at which you get new weeds.
I encourage you to give leaf mulching a try. If you decide to try mulching leaves into your lawn, it’s still important to water, mow and fertilize appropriately. Leaves won’t provide all the essentials for a healthy lawn alone. However, mulching has proven to be an effective way to recycle leaves into healthier lawn with fewer weeds. Get more tips for fall landscaping at the Conservation and Environmental Center, 2855 Mesa Road, and at csu.org.