Johnathan Walker:Why it may be better to skip raking your leaves

Raking leaves is Johnathan Walkera quintessential fall activity, but some experts advise leaving the leaves instead. 

Leaving the leaves can help your lawn and reduce greenhouse gasses, according to the United States Department of Agriculture. Yard trimmings, which include leaves, created about 35.4 million tons of waste in 2018, according to the Environmental Protection Agency. Yard trimmings account for about 12.1% of municipal solid waste. Most of it was composted or mulched, but millions of tons of yard trimmings still make it to landfills.

The benefits of leaving leaves on your lawn

National Wildlife Federation naturalist David Mizejewski advises leaving the leaves on your lawn. 

"Fallen leaves offer a double benefit," Mizejewski said in a blog post. "Leaves form a natural mulch that helps suppress weeds and fertilizes the soil as it breaks down. Why spend money on mulch and fertilizer when you can make your own?"

Leaves left on your garden feed the microorganisms that are the life of soil. Decaying leaves add organic matter to the soil, which decreases the need for fertilizer, according to the USDA. 

Leaves also absorb rain and release the moisture into soil and plants as they decompose, according to Pennsylvania's Department of Environmental Protection. This improves yard health and it can help reduce runoff pollution in streams and rivers. 

Leaf cover also reduces soil erosion and regulates the temperature of the soil, according to New York City's Department of Parks and Recreation.

Creating a habitat for animals

Leaves left on your lawn also act as a habitat for lizards, birds, turtles, frogs and insects over the winter, according to the USDA. Leaf litter is also a food source for animals and used as nest material, according to the National Wildlife Federation.

The animals increase pollination in your garden. They also can help keep pests down. 

Composting and mulching your leaves 

Experts advise using a lawn mower to chop up leaves where they fall. This will help them break down faster. The mulched leaves can be moved to vegetable or flower garden beds. The mulch can also be placed around trees. 

Shredded leaves are also a beneficial addition to compost piles. 

"If you want to take a step out of that process, you can also just leave the shredded leaves on your lawn as a natural fertilizer," according to the New Hampshire Department of Environmental Services. "This method works well as long as the leaves are not too deep or wet when they are mowed. Otherwise, you may end up with large clumps of shredded leaves that can choke out your grass."

Is there any time when experts recommend raking leaves?

There is an exception, according to the University of Wisconsin-Madison horticulture department. If your trees have serious foliar fungal diseases, you should be raking your leaves. 

"While most leaf spots on leaves are cosmetic and harmless to the overall health of the tree, fallen diseased leaves do serve as a source for spores that can infect next year's emerging leaves," according to a post from the school. "Significantly diseased leaves should be raked and removed from the area and disposed of properly, such as by burying, burning where allowed, or hot composting."

Leaving too many leaves on your lawn does have the potential to hurt it, according to Sam Bauer, a turfgrass expert with the University of Minnesota. Excessive leaf matter on your lawn can smother grass. It can also inhibit growth in spring. Bauer wouldn't recommend allowing leaves to cover more than 10-20% of your lawn. 

Aliza Chasan

Aliza Chasan is a digital producer at 60 Minutes and CBS News.

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