Should you rake your leaves?

Few fall chores start more arguments. Turfgrass researchers, wildlife groups, water-quality scientists, and health and fire agencies have all weighed in, and they don’t all agree, partly because each is looking out for something different. Here’s what each side says, so you can weigh it against your own yard.

The case for leaving them

For the lawn and the soil

The best-known lawn research comes from Michigan State University, where turfgrass scientists began mowing shredded leaves into test plots in 1990. Mulching in 50 to 100 pounds of dry leaves per 1,000 square feet each fall did the grass no harm, soil organic matter went up without changing the soil’s pH, and plots that got maple leaves had fewer broadleaf weeds. Even much heavier rates, up to the equivalent of leaves piled 6 to 18 inches deep before mowing, left some litter visible in spring that disappeared as the grass grew (Michigan State University).

A later Michigan State study found that mulched maple and oak leaves cut dandelions by up to 80 percent after one application, though the effect was smaller after two, and the researchers said leaves shouldn’t replace herbicides where tight weed control is the goal (ScienceDaily, on research by Michigan State). Turf specialists at Kansas State and Purdue describe the same results: no long-term effect on turf quality, thatch, or soil tests, and no added thatch or disease from mulching oak and maple leaves (K-State, Purdue).

Leaves also carry nutrients. UConn Extension, citing earlier research, says a 2-inch layer of leaves mulched into a lawn over a fall adds roughly 150 pounds of nitrogen, 20 of phosphorus, and 65 of potassium per acre, and says lawns may then need less fall fertilizer where quick recovery from heavy use isn’t a priority (UConn Extension). In a 2024 study of suburban Maryland yards, ones raked for many years had slower leaf decomposition and up to 24 percent less carbon in the soil, and a year or two of leaving the leaves didn’t undo it (Ferlauto and others, University of Maryland).

For insects and wildlife

The leaf layer is winter housing. Bumble bee queens dig an inch or two into the soil to hibernate, and the leaves above them act as insulation. Luna moth cocoons and swallowtail chrysalises look like dead leaves and spend the winter among them, and the red-banded hairstreak butterfly lays its eggs on fallen oak leaves (Xerces Society). Many firefly larvae live in leaf litter and soil, sometimes for more than a year before they become adults (National Wildlife Federation).

Salamanders, wood frogs, toads, box turtles, chipmunks, and shrews use leaf litter too, and ground-feeding birds such as thrushes and towhees forage in it (National Wildlife Federation). In a University of Maryland study of 20 homeowners’ yards, the number of moths emerging fell by almost half where leaves had been removed (University of Maryland).

For landfills and air quality

In 2018, Americans generated about 35 million tons of yard trimmings, roughly 12 percent of all municipal trash. About 63 percent was composted, but around 10.5 million tons still went to landfills (U.S. EPA). Gas equipment adds its own cost: California’s Air Resources Board says an hour of running a commercial gas backpack leaf blower puts out as much smog-forming pollution as driving a car about 1,100 miles (California Air Resources Board). That cost comes from the equipment, not the leaves; raking by hand or using electric tools avoids it.

The case for raking them

For the lawn

The same turf experts who favor mulching warn about thick, whole leaves. A heavy layer left on the grass can smother and kill it and encourage snow mold over the winter (Purdue University). Under a mat of leaves, grass can’t make and store food before winter, and the patchy dieback that follows opens space for weeds (Iowa State University Extension). Leaves still lying on the lawn in spring can slow its green-up (UConn Extension).

For lakes and streams

Leaves that end up in the street are a different matter from leaves in the yard. In a U.S. Geological Survey study in Madison, Wisconsin, clearing leaves from streets before it rained cut the phosphorus in storm runoff by 84 percent. Without leaf removal, fall leaves were the source of more than half the year’s phosphorus in that runoff, not counting winter (U.S. Geological Survey). That phosphorus flows to lakes and streams, where it feeds algae blooms (Minnesota Sea Grant).

For ticks

The CDC lists clearing leaf litter among the steps to make a yard less friendly to blacklegged ticks, which carry Lyme disease (CDC). Where leaves end up matters too: in a New Jersey study, yard edges where leaves were raked or blown into piles two to three times deeper than normal had about three times as many young blacklegged ticks the next spring (Entomology Today, on research by Jordan and Schulze).

For fire safety

In wildfire country, dry leaves are fuel. California’s fire agency advises removing dead leaves and pine needles from the yard, roof, and gutters within 30 feet of a home, and keeping the first 5 feet clearest of all (CAL FIRE).

For sick trees

Some leaf diseases spend the winter on the fallen leaves and reinfect the tree in spring. Apple scab is one; gathering up infected leaves reduces it, though UConn notes it may not be worth the effort if your trees are close to a neighbor’s apple trees (UConn Extension). For tar spot on maples, University of Maine Extension calls raking and destroying infected leaves in fall the most effective control (University of Maine).

Because the rules say so

For many people the choice isn’t theirs. In a 2026 National Wildlife Federation survey, 52 percent of respondents said a homeowners’ association or local rule requires them to remove leaves (National Wildlife Federation).

Where the experts don’t line up

What people do in between

Leaving leaves isn’t all or nothing, and several in-between practices come up again and again in extension and wildlife guidance:

• Mow while you can still see grass. Several extension services suggest mulching while the grass still shows through the shredded leaves (Colorado State, K-State). UConn suggests no more than about 20 percent of the lawn should still be covered after each pass (UConn Extension).
• Move them instead of removing them. Raking leaves into beds or under trees, in a layer around six inches deep, keeps much of their value for insects, according to Max Ferlauto on the Xerces Society’s podcast (Xerces Society). UConn suggests shredded leaves 4 to 6 inches deep in beds, kept about 6 inches back from plant crowns.
• Keep piles away from where people walk. That’s the tick researchers’ suggestion for yards in Lyme country.
• Compost them or make leaf mold. A moist pile or wire bin of leaves breaks down into crumbly leaf mold in a year or two. A UGA Extension Master Gardener advises keeping walnut and pecan leaves out of leaf mold (UGA Extension).
• Pull the problem leaves. Leaves from diseased trees, leaves near the house in wildfire areas, and leaves headed for the street are the ones most often singled out for removal. UConn also advises against moving leaves from a yard with invasive jumping worms.
• Use the town’s program. Many towns collect leaves for composting, which keeps them out of landfills and storm drains.

What makes sense depends on what you’re weighing: the lawn, wildlife, water, ticks, fire risk, or the rules where you live. Different experts put those in a different order.