Homesteading, Gardening, and Off-Grid Living

Mulching With Grass Clippings: Benefits and Drawbacks

By: Zac Friedman

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When mowing your lawn, you have two options when it comes to grass clippings. You can bag them or mulch them and leave them on your lawn. In this guide, I outline the benefits and drawbacks of mulching with grass clippings. I’ll also outline how to properly mulch with grass clippings and outline some alternative uses for grass clippings. 

What is Grass Mulching?

Grass mulching is a mowing technique where grass clippings are finely cut and distributed back over the lawn during the mowing process. It’s a way to cut your lawn without having to collect the clippings. 

Unlike ordinary mowing practices, grass mulching mowers are designed to cut the grass into tiny particles. These minute grass clippings then settle down to the soil level, where they decompose naturally. This releases essential nutrients back into the soil. In essence, grass mulching promotes a recycling ecosystem, turning grass clippings into natural fertilizers, enhancing soil quality.

The secret behind effective grass mulching lies in the type of lawn mower used. To mulch properly, you need to use a mulching lawn mower. Mulching mowers come equipped with specialized blades, often referred to as “mulching blades”. They also have a mower deck baffle system. It’s also possible to install a mulching kit on a regular mower to convert it into a mulcher.  specially 

These mower blades cut, recut, and finely chop grass clippings into tiny pieces before evenly distributing them across the lawn’s surface. In a well-executed mulching process, the lawn gets a clean, freshly mowed appearance, and the tiny clippings quickly make their way down to the soil without smothering the grass.

It’s important to distinguish that grass mulching is not simply leaving grass clippings on the lawn’s surface. Leaving clippings on the lawn results in larger, more noticeable pieces of plant material that might not decompose as quickly. For best results, you need to use a mulching mower that finely cuts the grass. 

Mulching with Grass Clippings pin

Pros and Cons of Grass Mulching

Pros

  • Provides nutrients for the soil
  • Helps with water retention
  • Reduces waste
  • Saves time and money
  • It will make your lawn look better
  • Can reduce thatch buildup

Cons

  • You have to mow more frequently
  • Can spread weed seeds
  • Clippings can build up
  • Can smother the grass

Grass Mulching Benefits

Grass Clippings Provide Nutrients for the Soil

When grass clippings are reintroduced to the lawn, microorganisms in the soil naturally decompose them. The decomposition of organic material releases important nutrients like nitrogen, potassium, and phosphorus back into your soil. When you bag the grass clippings, you lose these valuable nutrients. 

These nutrients provide a number of benefits for your lawn. First, they promote soil fertility. These are elements that your lawn needs for stong and healthy growth. They also reduce the need for synthetic fertilizer. They work as a  natural fertilizer for your lawn. In addition, the mulch encourages beneficial microbial activity.

Water Retention

The grass clippings form a protective layer that shades the soil. This helps to regulate soil temperature. This reduces moisture evaporation from the soil. This helps to maintain the soil’s moisture levels. If you live in a hot and dry climate, this is really important. 

There are a number of benefits of this moisture retention. First, you don’t have to water as frequently. This saves you time. You also don’t have to use as much water to keep your lawn green. This saves you money. It’s also better for the environment. You’re not using as much water. Your grass also won’t dry out and turn brown as quickly. 

Reduce Waste

Mulching with grass cuttings is a great way to significantly reduce waste and promote environmental sustainability. When you bag your lawn clippings and throw them away, you’ll use plastic bags to hold the clippings. Thees bags end up in landfills. In these landfills, they become a persistent environmental burden. Plastic bags take decades to decompose. They can also introduce microplastics into the environment. 

Yard waste itself  accounts for approximately 12% of landfill inputs, according to this article from the EPA. That’s significant.  Yard waste contributes substantially to waste accumulation.

By mulching your grass and leaving it on your lawn, you can reduce waste.. Mulching grass clippings allows them to quickly decompose directly in your yard, circumventing the need for disposal in plastic bags and subsequent contribution to landfill waste. This approach fosters a closed-loop system where grass clippings are reused to nourish the lawn, transforming what was once considered waste into a valuable resource for lawn care. 

Mulching Saves Time and Money

When you mulch your grass clippings, you don’t have to spend time collecting and bagging the clippings. The mulching process allows the finely cut grass clippings to be distributed directly onto the lawn. You don’t need to touch them. You also don’t have to spend money buying large yard waste bags. 

Furthermore, grass mulch is a natural fertilizing agent, rich in essential nutrients. This means that lawns maintained with grass mulching requires less frequent fertilization. You also don’t have to spend as much money on fertilizer for your yard. 

Because grass clippings help maintain moisture, you don’t have to spend as much time watering. Your water bill will also be lower because you’ll use a smaller volume of water to keep your yard green. 

However, it is important to note that mulching may necessitate more frequent mowing to ensure optimal mulch size and distribution. If you let the grass grow too long, the mulch pieces will be too large. Long grass can clump up. They will build up and decompose slowly when this happens. The grass can also plug up the mower. 

Nevertheless, the cumulative time saved from reduced collection, bagging, fertilizing, and watering tasks presents grass mulching as an efficient and practical approach to lawn care. It is efficient. 

Your Lawn will Look Better

Grass mulching is a powerful tool for enhancing the aesthetic appeal of your lawn. Grass clippings, finely dispersed over the lawn, contribute essential nutrients back to the soil. This creates a lush and vibrant green carpet of grass. This constant replenishment of nutrients ensures that the lawn maintains its appearance. 

Mulching with grass clippings also aids in the retention of soil moisture, promoting a resilient lawn that can maintain its aesthetic appeal even in less-than-ideal conditions. If it doesn’t rain much or if you don’t water as often as you should, your grass will stay green longer. 

Mulching can Reduce Thatch Buildup

Thatch is a tightly interwoven layer of grass roots, stems, and debris that accumulates on the soil’s surface, acting as a barrier between the soil and the grass blades. A minimal layer of thatch can be beneficial. It provides insulation against temperature extremes and foot traffic. It can also help with water retention. 

An excessive thatch buildup causes several issues. It can impede water, nutrient, and air flow to the soil. It can also create a habitat conducive to pests and lawn diseases.

Mulching on a regular basis with finely chopped grass clippings can be a tool to help you stay in control of lawn thatch. Mulching fosters a thriving microbial environment in the soil. This encourages the breakdown of organic matter, including the thatch layer. When there are more beneficial microbes, they can break down the thatch faster. 

You have to strike a balance when mulching or you can increase the thatch layer too much. the introduction of too many grass clippings or clippings that are too large can contribute to thatch buildup, exacerbating the challenge.

Grass Mulching Drawbacks

You Have to Mow More Frequently

Mowing frequently ensures that the grass clippings produced are are small enough to filter down to the soil level. A general guideline, it’s best to mow around once per week during the mowing season. 

When grass is allowed to grow too long between mowing sessions, the resulting clippings tend to be longer. These longer clippings struggle to make their way down to the soil surface. Instead, they can clump and sit on top of the grass. 

This can lead to an accumulation of grass clippings on the lawn’s surface, potentially smothering the grass. This can turn into thatch. The clippings won’t decompose efficiently. It also doesn’t look very attractive having grass clippings sitting on top of your lawn. 

Mulching Can Spread Weed Seeds

One often overlooked issue with mulching with grass clippings is the potential of spreading weed seeds across the lawn. When weeds are present, there’s a risk of inadvertently disseminating weed seeds. The mower mulches the weeds along with the grass and spreads the weeds across the lawn. The weed seeds make their way to the soil where they can easily germinate and grow. 

This can lead to the proliferation of weeds within the lawn. The weeds can spread to your garden and your neighbor’s lawns. The weeds compete with your grass for essential resources such as nutrients, water, and sunlight. This competition can hinder the growth and vitality of your lawn, causing it to appear unkempt and less healthy. 

Furthermore, managing and eradicating the spread of weeds can be a challenging and time-consuming task, often requiring additional efforts and resources for maintenance and weed control. You may need to use more chemicals on your lawn to get the weeds under control.

If you have a lot of weeds in your lawn, continue bagging your grass clippings until you get them under control. You can weed by hand or with weed killer. Once the weeds are gone, you can start mulching. 

Grass Clippings can Build Up

Grass clipping buildup occurs when clippings are not finely cut or when they are excessively deposited during mulching. This prevents them from decomposing quickly and integrating into the soil effectively.

This accumulation of grass clippings creates several issues. A thick layer of mulch can smother the underlying grass, hindering its access to essential sunlight and air. This can lead to issues such as yellowing grass and uneven lawn surfaces. 

An excessive layer of grass clippings can also create a habitat that is conductive to pests and diseases. For example, fungal diseases can more easily develop in the clumps of grass. 

If you notice a buildup of grass clippings on your lawn, stop mulching and bag the clippings instead. You can also rake your lawn to remove some of the buildup of clippings. If you’re noticing buildup, it often means that you’re waiting too long between mowings and the clippings are too long to fall to the soil surface. 

Mulching can Increase Thatch Buildup

If you introduce too much mulch into your lawn or the the clippings are too large, they can contribute to thach buildup. This happens because the clippings can’t decompose fast enough. 

Thatch buildup can impede water and airflow into the soil. It can also prevent fertilizer and beneficial insects from reaching the soil. it can also promote disease and attract pests. In addition, excessive thatch buildup reduces your lawn’s tolerance to excessive heat and cold. 

If you notice thatch starting to build up, stop mulching and start bagging your lawn clippings. Give the thatch some time to decompose before introducing more mulch. If there is a lot of buildup, you can thatch rake* (amazon) or a dethatcher machine to remove the thatch.  

Can Smother the Grass

When clippings clump together on the lawn’s surface, they can smother your grass. The clippings create a barrier that hinders the essential flow of air and sunlight to the underlying grass.

This clumping and smothering creates an environment where the grass struggles to breathe and photosynthesize effectively, leading to issues such as yellowing, uneven growth, and overall lawn deterioration. 

Regular mowing helps to to prevent this. You want to maintaining the grass clippings at the optimal length. Iideally they should not exceeding one-third of the grass’s height. This ensures that they can decompose rapidly without overwhelming the lawn.

A robot mower mulching
Robot mowers are great for mulching

How to Mulch With Grass Clippings

When done correctly, mulching with grass clippings can enhance soil health, conserve moisture, and create a beautiful lawn. In this section, I’ll list of strategies and tips to optimize the grass mulching process.

Mow when your grass is at the right height

Maintain a mowing height that cuts only the top third of the grass blades. Shorter clippings decompose more quickly and are less likely to clump, facilitating a smoother mulching process. 

Use the proper mower

Consider using a mulching mower for optimized results. Mulching mowers are designed to cut grass clippings into smaller pieces that decompose faster, enriching the soil with essential nutrients more efficiently.

You also won’t have to mow quite as frequently when you use a mulching mower. The mower can mulch taller grass.

Also, be sure to choose a mower that is powerful enough to cut your grass reliably and evenly. Both electric and gass mowers can work well. Push mowers can also work well for grass mulching. 

It’s also important to make sure the blade is sharp. A dull blade will tear the grass. It can also cause the grass to clump up. 

Mow frequently

Ideally, you should mow around once per week to ensure that the clippings don’t get too long. This also ensures that the volume of clippings isn’t too great. The smaller clippings will decompose over the following week. 

Disperse the clippings properly

A mulching mower will automatically discharge the clippings over the area that you mowed. If you find that the clippings are starting to bunch up or form rows, use a rake or leaf blower to scatter them evenly across the lawn. 

Don’t mow when the grass is wet

Aim to mulch with dry grass clippings. Wet grass clippings tend to clump together, preventing them from distributing evenly and decomposing efficiently. This can inhibit soil aeration and sunlight penetration.

Monitor the volume of grass clippings produced

Avoid overwhelming the lawn or garden with excessive clippings. Aim for a light, even distribution that can easily integrate with the soil without smothering the grass. If you notice clippings start to build up, bag your grass for a week. This gives the existing clippings more time to decompose. 

Seasonal Considerations

Adapt your mulching practices based on seasonal needs. In hotter months, mulching can aid in retaining soil moisture. During cooler months, it can provide insulation to plants, protecting them from frost. During the growing season, your grass may grow faster so you may have to mow more frequently. During cooler months, the mulch may not decompose as quickly so you may have to bag some of it. 

Other Ways to Get Rid of Grass Clippings

If you don’t like leaving grass clippings on your lawn or if you have too many grass clippings, there are a few other uses for them including: 

Compost

Grass clippings in the compost
Grass clippings make great compost

You can compost fresh grass clippings. Adding grass clippings to your compost pile is a great way to increase the nitrogen levels. To create a more balanced compost, be sure to mix the grass clippings with other compostable items such as fruit and vegetable trimmings, dry leaves, coffee grounds, etc. 

Mulching

You don’t need to limit the use of grass clippings to your lawn. They can also be used in garden beds and vegetable gardens. If you have a buildup of mulch on your lawn, you can catch the clippings and spread them on top of the soil in the area you want to mulch. 

If you do this, ensure that the grass clippings are free of weed seeds to prevent unwanted growth.

Bag Them and Throw them Away

If you have too many grass clippings or if you simply don’t want to mulch them or compost them, you can bag them and throw them away. If you decide to do this, make sure you properly dispose of your clippings. Check with your local waste management company to determine how to properly dispose of them. If you have one, place them in your yard waste bin. If possible, consider using environmentally friendly biodegradable yard waste bags like these*. 

FAQ About Mulching with Grass Clippings

Is mulching good for grass?

Yes. Mulching is generally beneficial for grass when done correctly. Mulching with grass clippings contributes organic matter back into the soil, enhancing soil structure and fertility. It helps in retaining soil moisture, reducing the need for frequent watering. It also offers a natural, nutrient-rich alternative to synthetic fertilizers. 

It is essential to ensure that the grass clippings are evenly spread and not too thick, preventing issues such as lawn smothering or thatch buildup.

What is the best time to mulch?

The ideal time for mulching with grass clippings is in the spring and early summer. At these times of year, the grass is actively growing. The clippings can be effectively utilized to enhance soil fertility and moisture retention during warmer periods.

Is it better to mulch or bag your grass?

Mulching your grass clippings is the better option. Mulching returns vital nutrients back into the soil. The natural nutrients help your grass grow stronger roots and resist disease. Your grass will look green and beautiful as well. Mulching is also a more sustainable and eco-friendly option. It reduces yard waste. 

On the other hand, bagging might be preferable when dealing with lawns that have weed infestations or diseases. It helps in preventing the spread of unwanted seeds. Bagging can also be the better option if you want to use your grass clippings for another purpose such as mulching flower beds or composting. Assessing the specific conditions and needs of your lawn will guide the decision on whether mulching or bagging is the more suitable approach.

Final Thoughts About Mulching With Grass Clippings

When it comes to lawn care, mulching with grass clippings is a sustainable and environmentally friendly choice with a wide range of benefits. Grass mulching enhances soil fertility, increases moisture retention, and promotes a vibrant, healthy lawn. Of course, there are some drawbacks. You have to keep an eye out for thatch buildup, weed spread, and lawn smothering. 

Do you mulch with grass clippings? Share your experience in the comments below!

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