Most people don’t realize that grass clippings make great mulch.
In fact, there are many reasons to use grass clippings as mulch: They act as a natural fertilizer, provide moisture, reduce landfill use, prevent weeds, and reduce lawn care costs, among other benefits.
Natural Fertilizer
Leaving grass clippings on your lawn helps return essential nutrients to the soil. With roughly 4% nitrogen, 2% potassium, and 1% phosphorus, grass clippings act like a natural slow-release fertilizer for your lawn. By using them, you can cut fertilizer costs, protect water sources, and keep the soil free of chemicals in one fell swoop.
“Our research has shown that we can cut the fertilizer application rate almost in half when we return clippings with a mulching type rotary mower,” says Alec Kowalewski, Associate Professor at Oregon State University. “And on lawns growing in clay soils, I have produced acceptable quality turf for as long as 12 years without adding any fertilizer at all.”
But to make the most of your grass clippings, follow a proper mowing schedule. “Frequent mowing, about once a week during the growing season, will have a greater impact on turf quality than any other lawn care practice except irrigation in the summer,” Kowalewski adds.
See Related: Lawn Mowing Tips: How to Mow a Lawn the Right Way
Provide Moisture
Grass clippings are 80 to 85% water, so they help lock moisture into the soil. When soil moisture is optimal, grass grows faster, you water less, and your lawn becomes more resilient to heat or drought.
Moreover, as lawn clippings shield the lawn from direct sunlight and wind exposure, they help reduce water evaporation, saving up to 25% on your water bill.
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Regulate Soil Temperature
Grass clippings regulate soil temperature by acting as a natural insulator.
By covering the soil, clippings help reduce heat buildup and protect beneficial soil microorganisms from heat stress. In cooler weather, they trap heat and prevent temperature swings that could otherwise stress grass and plant roots.
Reduce Landfill Use
Mulching your yard clippings reduces dump fees and keeps waste out of already-strained landfills.
A 2018 report from the U.S. Environmental Protection Agency shows Americans generate about 34.7 million tons of yard trimmings per year, with 10.8 million tons ending up in landfills. That’s down from previous decades.
This is partly because people now mulch or compost their trimmings more often. Also, state governments have taken action to keep yard trimmings out of their landfills.
See Related: How to Compost Grass Clippings
Prevent Weeds
Weed seeds depend on sunlight to germinate and grow. But when you leave grass clippings on your lawn, it creates a barrier, so weeds won’t be able to sprout as easily. Alternatively, spread the clippings around your plants or garden beds.
You can also use clippings to smother existing weeds and restrict their access to light and air, cutting off their essential elements for photosynthesis. Fewer weeds means less manual labor pulling them or less need for herbicides.
Improve Soil Health
Another cool benefit of grass clippings is that they provide the soil with organic matter necessary for maintaining fertility and health. More specifically, they help in the following ways:
- Improve microbial activity (this includes bacteria, microbes, and fungi that play a crucial role in soil health).
- Help with nutrient cycling, maintaining a steady stream of macronutrients like nitrogen, phosphorus, and potassium, and micronutrients such as copper, iron, and manganese.
- Increase soil aeration by creating air spaces necessary for root respiration, establishment, and growth.
- Improve the soil’s ability to hold water, as the organic matter soaks it up like a sponge, helping to reduce runoff and keep the ground moist.
- Maintain a balanced soil pH, helping grass and plants grow strong and healthy.
- Reduce soil erosion by improving soil texture. Healthy soil is less prone to breaking apart and blowing away due to wind or rain.
See Related:
- What Is Aeration? [Video]
- Why, When, and How to Test the Soil pH of Your Lawn
- How to Control Erosion in the Yard
Reduce Lawn Care Costs
Using grass clippings as mulch is a cost-effective approach to lawn care. Here’s how it helps you pay less:
- Cuts cost on mulch and fertilizers. Instead of purchasing commercial mulches and costly synthetic fertilizers, you can use grass clippings as a sustainable way to provide your lawn with mulch. It’s free.
- Eliminates disposal costs. This includes everything from bagging and hauling the clippings to paying for grass removal.
- Reduces watering costs. Using grass clippings, you won’t have to water your lawn or garden as much. Clippings help conserve soil moisture when it rains or when you irrigate. This means lower water bills.
- Supports eco-friendly lawn care practices. If you value sustainability, using your grass clippings as mulch is the way to go. This eco-conscious approach to lawn care reduces reliance on non-renewable resources and promotes a healthier ecosystem since it eliminates inorganic mulches and their production.
See Related: How Much Does Grass Removal Cost?
When You Should Bag Your Grass Clippings
There are times when you should bag grass clippings and not leave them on the lawn.
- If your grass clippings are particularly dense or long, consider bagging them to avoid a thatch problem. Dennis L. Martin, Oklahoma State University Turfgrass Extension Specialist, says infrequent mowing produces long grass clippings that take longer to decompose into the soil. “Although grass clippings do not normally cause thatch, infrequent and improper mowing can lead to instances of grass clippings causing thatch problems,” Martin adds.
- If your lawn is affected by diseases or pests, bagging your lawn clippings can help contain the infestation and prevent spreading.
- If you prefer a more manicured lawn, it’s best to bag your clippings.
- If you’re going to overseed your lawn with new seed, bag the clippings right before overseeding. It allows the new seedlings to breathe and grow properly.
- If you’ve recently fertilized your grass or applied chemicals, bag your clippings to contain the chemicals in the desired areas. Otherwise, clippings can spread the products across your entire lawn.
See Related:
- What is Thatch in Your Lawn?
- Common Lawn Diseases and How to Identify Them
- How to Aerate and Overseed Your Lawn
- How to Fertilize Your Lawn
FAQ About Using Grass Clippings as Mulch
Yes, if you bag the lawn clippings to use them in flower beds or other areas, let them dry a day or two before using them as mulch. This prevents matting and odors and reduces the risk of suffocation and fungi.
Remember never to mow wet grass, as this can tear it up and create ragged edges. It can also cause grass clippings to clump together and clog or damage your lawn mower.
If your clippings are wet, spread them into a thin layer on your lawn, periodically raking and turning them to expose all sides to air and sunlight. Do it when there’s no rain in the forecast to speed up the process, which may take a few days.
See Related: How to Prevent Grass Clumping When Mowing
No, grass clippings do not normally cause thatch. People used to think that leaving grass clippings on the lawn (also known as grasscycling) caused thatch buildup. But thatch primarily comprises living and dead grass stems, roots, and rhizomes, not grass clippings.
“Virtually all research conducted with turf has shown that grass clippings do not increase thatch,” notes Kowalewski. “In most cases, thatch increases as mowing height increases.”
Absolutely. As the composting process generates heat, the clippings contribute nitrogen for your raised garden beds and vegetable garden plots.
Always balance carbon and nitrogen to achieve a healthy compost mix. Use both brown and green materials in a 3:1 ratio (3 parts brown, 1 part green).
● Brown elements are dry and carbon-rich. They can be dry leaves, straw, hay, paper, cardboard, or wood chips.
● Green elements are moist and nitrogen-rich. They could be anything from the grass clippings themselves to kitchen scraps, coffee grounds, fresh plant trimmings, and green leaves.
On the whole, you won’t need to water the compost pile when blending in the clippings. But if the grass is dry, sprinkle some water on the pile.
Be sure the clippings are pesticide- and herbicide-free before adding them to the compost pile.
See Related:
● How to Build Your Own Raised Garden Beds
● Digging In: 11 Steps to Start a Vegetable Garden
Grass clippings provide the most health benefits to:
● Leafy and fruiting vegetables, including tomatoes, peppers, lettuce, kale, and spinach
● Herbs, including cilantro, basil, parsley, dill, and lemongrass
● Perennial plants and flowers
● Fruit trees, including apple, peach, plum, and pear
● Bushes and shrubs
● Creeping ground covers, including creeping thyme, Irish moss, ajuga, periwinkle, and sedum
See Related:
● 10 Flowering Shrubs to Make Your Landscape Pop
● 15 of the Best Ground Cover Plants
Get Expert Help for Your Yard
We’ve already discussed the many benefits grass clippings provide when used as mulch. But if you’re unable or unwilling to mulch your own yard, no worries.
LawnStarter can put you in touch with a local lawn care pro who can mow your lawn and leave the grass clippings there for you.
Main Photo Credit: Ivan Radic / www.flickr.com / CC BY 2.0
