Mulching is great for your lawn for a number of reasons. Whether you are mulching leaves or returning lawn clippings back into the lawn, mulching saves time, money, labor, and it is a great soil amendment. There is really no need for raking, bagging, or hauling away either leaves or clippings. Here are the essentials you need to know.
Mulching Lawn Clippings
Almost without exception, lawn clippings should always be mulched back into the lawn. The benefits of mulching lawn clippings are too numerous and valuable to ignore. From providing nutrients for the soil to saving significant amounts of time and money, mulching the lawn clippings makes sense. Similar to mulching leaves into the lawn in the fall, lawn clippings add valuable organic matter to the soil.
Mulching is best accomplished with a mulching mower, which is just like any other mower but with a few modifications. Mulching kits are usually an option available to mowers at the time of purchase, but mowers can easily be retrofitted as well. Special "mulching" blades with extra cutting surfaces are used in conjunction with added baffling underneath the mower. The output or chute is blocked to trap the clippings underneath the deck. The baffling helps move the clippings around and allows them to be cut multiple times and blown down into the surface of the lawn.
Grass Clippings and Thatch Buildup
Grass clippings do not cause thatch buildup. They consist mostly of water, and the remaining tissue is broken down through microbial activity. Grass clippings may add to an existing thatch problem, but as long as the lawn is mowed regularly and a mulching mower is used, mulching lawn clippings into the lawn will not cause thatch buildup. Clumping may occur under wet or overgrown conditions. Care should be taken to avoid clumping and address it when it occurs to avoid smothering the grass.
Recycling grass clippings back into the lawn can account for up to one pound of a lawn's annual nitrogen requirements. A typical lawn needs up to 4 pounds of nitrogen annually for healthy growth. Returning the clippings to the lawn can effectively cut out one full fertilizer application, saving time, money, and labor. Clippings are rapidly devoured by worms, beneficial bacteria, and fungi, increasing the diversity and activity of the intricate food web.
With the overall goal of an organic or natural-based lawn care program being to achieve 5 percent organic matter in the soil and most lawns at around only 2 to 3 percent. It can take years of topdressing with compost, mulching leaves, and recycling grass clippings to increase the organic matter by even 1 percent, so there is no better time to start than now.
If the soil biology benefits are not enough to start mulching grass clippings back into the lawn, then maybe the financial rewards will help. A collection system on a lawnmower is far more expensive than a mulching kit. The more times clippings are handled, the more labor is involved. A collection system needs to be emptied, and the clippings then need to be put somewhere, either on-site or taken away.
If these extra steps do not increase the overall costs of a lawn care service, it certainly contributes to labor, fuel, and machinery maintenance budgets. If clippings are trucked off-site, where do they go? Tipping fees may be involved if they are taken to recycling facilities. If they are kept on site and used in a compost pile, care must be taken with regards to pesticide usage and composting chemical pesticides.
Situations to Skip Mulching With Clippings
Clippings can be collected, rather than mulched back into the lawn, if there are an abundance weeds such as dandelions and crabgrass in the lawn. Collecting the clippings around the time the weeds go to seed may help reduce the spread of weed seeds throughout the lawn during certain times of the year. If the lawn has gone un-mowed for more than a week due to rain or some other circumstance, it may be wiser to collect the clippings or, at the very least, mow over the clumps several times to distribute them better.
Clippings may not break down effectively in a conventionally maintained lawn if there has been repeated use of chemical pesticides and synthetic fertilizers. Insecticides for grub prevention can kill much more than the target pest and can render a lawn almost lifeless. Synthetic fertilizers increase the salts present in the soil, which can also reduce soil biology. A lack of microbial activity and earthworms may inhibit the amount of decomposition necessary to break down lawn clippings.
Mulching Leaves Into the Soil
For fall leaves, it turns out that you should be mulching them and returning them to the lawn. If there is an abundance, use them as mulch for gardens and planting beds or as filler for your compost pile. Don't put them on the curb, especially if they are bound for the landfill. Leaves are free organic matter and should be used on the property they came from when possible.
A study from Michigan State University indicates that mulching is 100 percent beneficial for the lawn. Oak leaves and maple leaves were mulched and redistributed through the lawn and found to have a negligible or beneficial effect on turf quality and color. Mulched sugar maple leaves even displayed an inhibitory effect on broadleaf weed seeds such as dandelion.
While the study somewhat reveals a negligible effect of mulch on the lawn, mulching the leaves back into the lawn is cost-effective and labor-saving compared with other methods of dealing with leaves. Mulching leaves is inherently better for not just the biodiversity and organic matter of the soil but also the greater community by keeping them out of bags and landfills.
Mulching leaves into the lawn adds organic matter, which most soils are lacking. Mulched leaves get broken down by earthworms and microorganisms and turned into plant-usable organic matter. In an organic lawn care environment, mulching makes perfect sense as the benefits are agronomic, financial, and environmental.
Stay on a Lawn Care Program
Many people who share negative views on mulching leaves in the fall have stories about their lawn being smothered or grass becoming weak and thin. For whatever reasons, the health of the lawn is blamed on the mulched leaves.
There is usually another factor, though. Soil fertility still needs to be maintained with fertilizer applications. A layer of mulched leaves needs nitrogen found in lawn fertilizer to assist in the breakdown process and to avoid a mat layer of mulch which can inhibit nutrient, water, and air from penetrating into the soil. Even organic lawns still benefit from an organic fertilizer application as mulched leaves are an amendment for the soil, not a replacement for fertilizing.
To avoid disappointing results with mulching leaves into the soil, practice some common sense guidelines. Do not mulch to the point where the grass is smothered. The lawn should still be vertical and visible through the layer of mulched leaves. In certain areas, it may help to spread the mulch around from thick spots to areas with thinner mulch distribution.
If there is an overwhelming abundance of leaves, it may be wise to collect a portion to use in flower beds, gardens, or compost piles. The lawn is only one beneficial area to use mulched leaf material. The overall goal should be to avoid raking, collecting, handling, and disposing of all leaves offsite. This would save untold quantities of money, labor, and resources.
What to Do With Lawn Clippings. University of Minnesota Extension.