Should I Rake or Mulch My Leaves?

Colorful autumn leaves are one of fall's greatest pleasures. But beautiful autumn color quickly translates to leaves on your lawn. When lush, healthy grass is your goal, ignoring fallen leaves isn't an option. But that doesn't mean raking and bagging leaves is the way. Mulching leaves into your lawn is easier — and better for your lawn and the environment. By understanding answers to the following questions, you can mulch your way to a healthier lawn:

Why can't leaves just stay on the lawn?

Like all plants, your grass has basic requirements for keeping it lush and green. At the top of the list are sunlight, water, nutrients and oxygen. And a mat of fallen leaves interferes with them all. Think of it like growing grass in dense shade, only multiplied several times.

Without sunlight, your fall lawn can't carry out photosynthesis and replenish reserves before winter comes. Water and nutrients can't penetrate leaves to nurture and nourish grass roots. Plus, poor air circulation sets the stage for fungal lawn disease. Come spring, you're faced with bare lawn spots and a weak, thin lawn. And because leaves keep soil colder in spring, you'll wait longer for grass to turn green.¹

Fallen leaves don't just disappear. Maple leaves break down faster, but oak and sycamore leaves can take more than a year to decompose.² By learning the best way to remove leaves from your yard — and doing it — you prevent your grass from suffering.

Left unmanaged, fallen leaves can smother grasses and encourage lawn disease.

Is mulching leaves better than raking?

Whether you mulch or bag leaves, removing leaves keeps them from smothering your lawn. But shredding leaves into tiny pieces by mulching them has benefits that raking and bagging don't.

Tree leaves contain about 2% nitrogen.¹ To stay green, thick and healthy, your lawn grass needs nitrogen in a greater quantity than any other essential plant nutrient. That's why the first number in the N-P-K on most lawn fertilizer labels is the largest.

By mulching leaves instead of raking, you treat your lawn to natural fertilizer and beneficial organic matter. Plus, mulching leaves into your lawn can discourage weed seeds from germinating and reduce common lawn weeds such as dandelions and crabgrass significantly.^1,3 In many cases, you can mulch leaves during regular lawn mowing. That means more free time for you.

Keep in mind that raking and toting leaf bags are strenuous aerobic activities, too. For some people, the cardiac health risks of raking and bagging leaves rank right up there with shoveling snow.⁴

Mulching leaves into your lawn can help reduce unwanted weeds.

What equipment do I need to mulch leaves?

You can learn how to mulch leaves without investing in a lot of extra equipment. Mulching leaves with a regular lawn mower can get the job done. If you deal with large quantities of heavy leaves in a short time frame, a mulching mower for mowing leaves into your lawn may make sense.

A regular lawn mower cuts grass blades and shoots grass clippings out of the side or into a bag. Mowing leaves into lawn grass works the same way. Leaves must be mulched into small pieces that can filter down to soil, so a regular lawn mower may require a few trips back and forth. You can also purchase mulching blades for your regular mower. Depending on the amount of leaves you have to mulch, these specially designed mulching blades may decrease the number of passes you need to make across your lawn.

In contrast, a mulching mower keeps grass clippings — and leaves — under the mower deck. The blades cut clippings several times, so smaller pieces result. Mulching mowers help enhance your lawn's sustainability during regular mowing, too. Mulching grass clippings into your lawn delivers an all-natural 4-1-2 fertilizer every time you mow.⁵

Dedicated leaf mulchers come in push, pull and handheld options. They're designed especially for shredding leaves, not cutting grass. Popular models include cordless mulchers that switch from leaf blowers into leaf vacuums that shred and collect mulched leaves for other uses.

Mulching mowers chop grass and leaves into small pieces.

How and when should I mulch leaves with a mower?

The best approach to mulching leaves with a mower is being proactive. Plan on mowing leaves instead of raking as part of your regular fall lawn maintenance. Start as soon as leaves begin to fall. Mowing a few leaves is simpler than mowing a lot, and dry leaves mulch better than wet ones. When mulching while mowing, use your regular mower height for mulching leaves.

As lawn mowing slows down and falling leaves speed up, mulch with your mower at least once a week — twice if needed. Use the highest mower height for mulching leaves. University research indicates you can mulch up to 6 inches of leaves on your lawn as long as you mulch leaves into small pieces.3 Mulching mowers and leaf mulchers can handle larger leaf volumes more efficiently.

Whether your lawn care calendar covers northern regions or southern zones, mulching enhances the impact of other fall tasks. Late summer to early fall is the perfect time for overseeding your cool-season lawn with premium grass seed such as Pennington Smart Seed grasses or prepping your grass with winterizing fertilizer such as Pennington UltraGreen Winterizer Plus Weed & Feed Fertilizer 22-0-14. By mulching leaves into your lawn, you help ensure your grass gets all the benefits you can put into it.

Mulching leaves helps ensure your grass gets the full benefit of fertilizers and other fall tasks.

Does mulching leaves help the environment?

If you're still wondering whether should you rake leaves, look past your lawn. The benefits of mulching fall leaves go beyond supporting healthy soil and grass growth. Mulched leaves are an excellent addition to your compost pile, creating rich organic material for future garden use.² Used as garden mulch, shredded leaves help avoid fluctuations in soil temperatures that can damage plant roots. As mulched leaves decompose, they work as a soil amendment, adding organic matter and improving soil.

Mowing leaves instead of raking also helps to reduce landfills. The U.S. Environmental Protection Agency estimates that yard trimmings accounted for more than 7% of all municipal solid waste that ultimately ended up in landfills in 2018. That's about 10.5 million tons of un-composted, landfilled solid waste — and leaves make up 25% of that preventable waste.⁶

By mulching your leaves instead of raking, you can improve your lawn and benefit the environment as well. At Pennington, we're dedicated to helping you grow the best lawn possible and enjoy the results. We've been here for seed professionals and homeowners for more than 75 years — and we're here for you, too.

Always read product labels thoroughly and follow instructions.

Pennington and Smart Seed are registered trademarks of Pennington Seed, Inc.

UltraGreen is a registered trademark of Central Garden & Pet Company.

Sources:

1. J. Trappe, "Should I Mulch? Or Bag My Leaves This Fall?," University of Minnesota Extension.

2. P. Burns, "Leave the Leaves," North Carolina Cooperative Extension.

3. R. Finneran, "Mulch Leaves Into Turf for a Smart Lawn," Michigan State University Extension.

4. "Fall Yardwork Can Strain Your Heart," Cleveland Clinic.

5. C. Starbuck, "Grass Clippings, Compost and Mulch: Questions and Answers," University of Missouri Extension.

6. Facts and Figures about Materials, Waste and Recycling, "Yard Trimmings: Material-Specific Data," United States Environmental Protection Agency.