Reasons to Use Grass Clippings as Mulch

wheelbarrow filled with grass clippings

Grass clippings are often overlooked, but this simple and sustainable resource can keep your garden green and your plants healthy. From conserving water to preventing weeds, grass clippings can certainly pull their weight when nurturing your yard.

Let’s jump straight into all the reasons to use grass clippings as mulch and provide a host of nutrient-rich goodies for your landscape.

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Reasons to Use Grass Clippings as Mulch

In the past, it was commonly thought that letting grass clippings decompose on the lawn (also known as grasscycling) contributed to thatch buildup. But turfgrass researchers found that trimmed lawn clippings don’t actually cause thatch; using them as mulch is a sustainable way to manage lawn waste and promote a more robust ecosystem. 

Check out all the reasons why you should use grass clippings as mulch:

Grass Clippings Are a Natural Fertilizer

By mulching, you reduce your lawn’s fertilizer needs. “Mulching re-introduces essential minerals to your lawn that would otherwise be lost,” O’Rourke said. “For example, nitrogen, phosphorus, and potassium are all preserved by utilizing the mulch, reducing the need for artificial fertilizers to keep your lawn looking healthy.”

Leaving the mulch in your lawn returns several pounds of nutrients to your lawn each season. That’s “a considerable amount when typical recommendations suggest 2 to 5 pounds of actual nitrogen per 1,000 square feet of lawn annually,” notes Oregon State University’s Extension Service. 

Using mulch allows you to skip the time and expense of a nitrogen fertilizer while still maintaining a healthy lawn. The table below shows how much nutrients are in lawn clippings.

Nutrient TypeAmount Mowed Off in One Growing Season (Per 1,000 Square Feet)
Nitrogen4.8 Pounds
Phosphorus0.7 Pounds
Potassium2.6 Pounds
Source: The Lawn Institute, James B. Beard, “Turfgrass: Science and Culture”

Grass Clippings Provide Moisture

Lawn clippings serve as a protective barrier over the surface of the soil, shielding it from direct sunlight and wind exposure and reducing water evaporation. This is particularly beneficial during hot and dry periods, as it helps grasses and plants withstand drought stress.

Grass clippings also moderate soil temperature, preventing the soil from becoming overly heated. They maintain a stable and cool soil environment, contributing to optimal soil moisture levels.

Grass Clippings Reduce Landfill Use

Mulching your yard clippings reduces dump fees and keeps yard 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. That’s 69.4 trillion pounds. But just 10.8 million tons end up in landfills. That’s down from 27 million tons in 1980.

In part, that’s because people have changed their habits and now either mulch or compost their trimmings. Also, state governments have taken action to keep yard trimmings out of their landfills.

Grass Clippings Prevent Weeds

Weed control is essential. A layer of grass clippings can serve as a natural weed deterrent, blocking sunlight and suppressing weed seed germination. Weeds need sunlight for photosynthesis, the process they use to produce food. By preventing sunlight penetration, grass clippings impede the germination and growth of weed seeds.

A layer of grass clippings also will make it more challenging for weed seeds to come into contact with the soil surface and establish themselves, thus reducing the need for herbicides and manual weeding.

Grass Clippings Improve Soil Health

Another cool benefit of grass clippings is that they provide the soil with organic matter necessary for maintaining fertility and health. Here’s a detailed breakdown of the benefits mulching with grass clippings provides:

  • Improves microbial activity (this includes bacteria, microbes, and fungi that play a crucial role in soil health)
  • Helps with nutrient cycling, maintaining a steady stream of macronutrients like nitrogen, phosphorus, and potassium, and micronutrients such as copper, iron, and manganese
  • Increases soil aeration by creating air spaces necessary for root respiration, establishment, and growth
  • Enhances the soil’s water retention capabilities because the organic matter acts as a sponge, reducing water runoff and managing moisture levels
  • Maintains an appropriate soil pH, preventing fluctuations and creating a more favorable environment for healthy grass and plant growth
  • Reduces soil erosion by improving soil texture

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Grass Clippings Reduce Lawn Care Costs

Using grass clippings as mulch is a cost-effective approach to lawn care. Check out all the ways you can use grasscycling to increase your savings and maintain a spectacular lawn at the same time:

  • Grass clippings are readily available – for free. Instead of purchasing commercial mulches and costly synthetic fertilizers, you can use grass clippings as a sustainable way to provide your lawn with mulch.
  • Grass clippings eliminate disposal costs. This includes everything from bagging and hauling the clippings to using waste removal services that may cost an arm and a leg.
  • Grass clippings reduce watering costs. By using grass clippings, you won’t have to water your lawn or garden as much. Why? A layer of clippings on the soil helps conserve soil moisture introduced into the soil via irrigation or rainfall, which means you won’t have to water as often. The end result? Lower water bills.
  • Grass clippings support 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.

When You Should Bag Your Grass Clippings

Bagging your grass clippings is recommended in certain situations. In fact, doing so is considered beneficial in the following cases:

  • If your grass has experienced a growth spurt and it’s particularly dense or long, you may consider bagging your clippings. Otherwise, thatch buildup may occur, hindering nutrient and water absorption.
  • If your lawn is affected by diseases or pests, bagging your lawn clippings can help contain the infestation and prevent further spreading.
  • If you prefer that tidy, manicured look to your lawn, mowing more frequently and bagging the clippings every time can help you achieve your goals. 
  • If you’re planning to overseed your lawn with new seed, it’s recommended that you bag your clippings at first to allow the new seedlings to breathe and grow properly.
  • If you’ve recently fertilized your grass or applied pesticides or herbicides, bag your clippings to contain the chemicals in the desired areas (at least until they’ve had a chance to penetrate the soil). Clippings can spread the products across your entire lawn, and that can be a problem if it’s not what you had planned.

Pro Tip: Remember to practice the one-third rule when cutting grass to promote a healthy, thriving, lush lawn. This reduces stress on your grass, prevents weakening, and boosts resistance to pests, diseases, and environmental stressors.

FAQ About Using Grass Clippings as Mulch

Should I Use Dry Grass Clippings as Mulch?

Yes, allowing the grass clippings to dry a day or two before using them as mulch is best. This prevents matting and odors and reduces the risk of weed seed germination. To dry your grass clippings, try one of these approaches:

  • Air dry – Collect your clippings, spread them out onto a flat, dry surface, and allow them access to the sun. This can be your driveway or a tarp that you can use for this purpose. The layer shouldn’t be thicker than 1-2 inches to prevent rotting and moisture accumulation, which defeats the purpose of drying your grass. For collection, you can use your lawnmower if it has a bag attachment or load the clippings into a wheelbarrow or bucket.
  • The rake and turn method – After mowing your grass, spread the clippings out into a thin layer on your lawn, periodically raking and turning them to expose all sides to air and sunlight. Do this when there’s no rain in the forecast to speed up the process, which may take a few days.

Can I Add Grass Clippings to My Compost Pile?

Absolutely. The heat of the composting process will contribute to fertile soil for your garden beds, raised beds, and vegetable garden plots.

On the whole, you won’t need to water the compost pile when blending in the clippings. But if the grass is dry, you’ll have to sprinkle some water on the compost pile. Missouri’s extension service recommends a 1:1 to 2:1 ratio of brown to green. Be sure the clippings are pesticide- and herbicide-free before adding the organic matter to the compost pile.

What Other Uses Do Grass Clippings Have?

With grass clippings, the possibilities are endless. Here are other ways you can turn grass clippings into an asset in your yard:

  • Use them to topdress raised garden beds for added nutrients, moisture, weed reduction, and soil aeration.
  • Use them to create paths in your garden.
  • Use them to feed livestock and create bedding for rabbits, birds, guinea pigs, and hamsters. Make sure they haven’t been treated with any pesticides or herbicides.
  • Use them to make liquid organic fertilizer for your plants and grass.

How Often Should I Add New Grass Clippings to the Mulch Pile?

We recommend replenishing the mulch pile as soon as it’s decomposed or thinned out. This usually means adding new grass clippings every few weeks, but use your better judgment and let the pile guide you.

Where Should I Use Grass Clippings as Mulch the Most?

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 groundcovers, including creeping thyme, Irish moss, ajuga, periwinkle, and sedum

Get Expert Help for Your Yard

We’ve already talked at length about the many benefits grass clippings provide when used as mulch. But if you’re unable or unwilling to mulch your own yard, professional help is just a click or phone call away. A local pro can mow your lawn and start you on your mulching journey – all so you can enjoy an outdoor oasis without fuss.

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Main Photo Credit: Ivan Radic / www.flickr.com / CC BY 2.0

Andie Ioo

Andie Ioo

In my free time, I enjoy traveling with my husband, sports, trying out new recipes, reading, and watching reruns of '90s TV shows. As a way to relax and decompress, I enjoy landscaping around my little yard and DIY home projects.