It’s the annual fall dilemma. The leaves that have fallen on the lawn need to be removed, but there are more on the trees. Should you rake them up now or wait until the limbs are bare?
Neither! Bag the rake, not the leaves.
Instead of raking leaves, stuffing them into lawn bags and hauling the bags to the curb, mow them with a mulching mower – a lawnmower with a specially designed high deck and a mulching blade that chops leaves into fragments as tiny as confetti. As the shredded leaves decompose, they will act as a natural fertilizer and weed control agent.
For those who insist on a spotless lawn year-round and might be concerned about what the neighbors will think of the brown leaf bits the mower leaves behind, don’t worry. The shredded leaves will filter through the grass and disappear from sight. In northern lawns that go dormant or in grasses such as Bermuda or zoysia that turn a dormant brown color in winter, the shredded leaves may even blend right in. Better yet, if you continue this practice each fall, in a few years mulching can help you have a luscious spring and summer lawn free of dandelions and crabgrass that will be the envy of people up and down the street.
Here’s a guide on how to take advantage of autumn leaves, the best free resource for your lawn.
The problem with fall leaves
Leaves that are not removed from your lawn block sunlight and air from reaching the grass. The problem becomes worse when it rains or there are early snows that turn fluffy layers of leaves into soggy mats. The lack of light and air circulation can cause turf diseases or, in a worst-case scenario, may even smother the grass and kill it.
Homeowners can easily solve this problem with a mulching mower. “Mulching mowers are designed with a high deck and are shaped so that the mulching blade spins leaves and grass more than once as it cuts them into small pieces,” said Kevin Morris, president of the National Turfgrass Federation. Just change the mower to its highest setting, remove the bag attachment and mow the leaves and grass, letting the shredded leaves and grass blades remain on the lawn. If you don’t have a mulching mower, an alternative is to buy a mulching blade from a hardware store a – mulching blades have special serrated edges – and attach it to the mower. Morris cautions, though, that regular lawn mowers may not shred leaves as well as a mulching mower because regular mowers may not re-circulate leaves inside the deck the way that mulching mowers do. Mowers with side shoots or old-fashioned push mowers can be used, but also are not as effective in shredding leaves into small pieces as mulching mowers. If you use a landscaping service, ask them to use a mulching mower in the fall and not bag the leaves.
When to mulch
The optimum time to shred fallen leaves is when you can still see some grass poking up through them. Depending on the number and size of trees on your property – or your neighbor’s – you may need to mow your yard more than once a week. Studies by turf grass specialists at Michigan State University show that up to six inches of leaves can be mulched at one time, depending on the type of mower you have. There’s also a common sense approach about when to mulch. If the leaves are so thick that they make mowing difficult, you may need to add the bag attachment or even rake them. You can also put the bag attachment on a mulching mower and spread mulched leaves on landscape and vegetable beds.
What not to do
Don’t wait until spring to mulch leaves and spread them on landscaped beds. If you place leaves on garden beds in the fall, they will biodegrade almost completely, if not completely, by spring. If, on the other hand, leaves are not placed on garden beds until spring, the decomposition process will compete with plants for nutrients just when the plants need it most, to make energy to produce the flowers you’ve waited all winter to enjoy!
Why mulching works
Micro-organisms that live in the soil beak down organic material such as leaves. Worms get in on the action, too. The roots of some grasses such as fescue can grow slowly in the fall and a mild winter and the decaying action of mulched leaves left on the yard will provide these roots with nutrients. Mulched leaves will biodegrade and disappear from the lawn by spring. The same type of activity with micro-organisms and worms that is happening in the lawn area is also happening in landscape and vegetable beds.
Shredding leaves with a mulching mower will save homeowners time and money. Mulching is faster and far easier on the back than raking. It’s also easier on the wallet. The decomposing leaves and grass cover the soil between the individual grass plants where weeds can germinate. MSU studies found that homeowners can attain a nearly 100 percent decrease in dandelions and crabgrass after mulching fall leaves for just three years. In addition to reducing the occurrence of weeds and the need to spend money on weed control products, mulched leaves keep the soil warmer in winter and cooler in summer and the nutrients provided by mulching reduce the amount and expense of fertilizer need to achieve green-up in the spring.
If you are using a side-discharge mower, begin mowing on the outside edge of your lawn, making sure that you shoot the leaves toward the middle of the yard. Mowing in this pattern also allows you to mow over the leaves more than once and keeps them from ending up on sidewalks, driveways and the road. If the leaves are still in fairly large pieces after your first pass, go back over the lawn at a right angle to your first cut.
Depending on how many hardwoods you or your neighbors have, you can use leaf blowers to blow leaves into landscaped beds or use a lawn vacuum to vacuum up leaves. Leaf vacuums will produce finely chopped leaves that are excellent for placing in flower or vegetable beds. When spreading leaves in garden beds, be careful not to smother ground covers.
Whatever you do, don’t let fall leaves get away. Use them somewhere in your landscape!
Related fall gardening stories on MNN: