Do Grass Clippings Help Grass Grow?


Many people prefer to leave grass clippings on their lawn after mowing. One of the most commonly mentioned benefits of doing this is that it actually helps grass grow. People often ask me whether this is true or not. 

Grass clippings help grass heal faster after trimming. They also help the grass grow by supplying nutrients to your lawn and moderating the soil temperature. There is a lot of nitrogen in grass clippings which is essential in the production of amino acids which help in protein synthesis to build the plant body. When they decompose, they supply the nutrients back to the soil hence improving your grass’ growth rate. 

Read on and find out more about the role of clippings in your garden and how to utilize them for a healthier, greener lawn.

Do Grass Clippings Help Bare Spots?

Dry grass clippings help bare spots to regain a layer of grass through the supply of nutrients and protection from high temperatures. They can also prevent insect infestation. 

Bare spots are basically areas without enough grass cover. This is caused by one or more of the following:

  • Prolonged drought that leads to the death of grass
  • Heavy “traffic” from human beings, animals, and locomotives
  • Corrosive chemicals such as acids
  • Weed, insect, or other infestation

When you spread a thin layer of grass clippings on the bald surface, it decomposes to organic manure rich in essential nutrients and minerals. The clippings also preserve moisture in the soil preventing evaporation and moderating the temperature of bald spots. 

As the nutrients get absorbed into the soil, the grass rhizomes get nourished and grow into a new grass cover, covering the bald spots.

Note that spreading wet clippings or a heavy layer of mulch may hinder the sprouting of underground grass rhizomes and cause a greater extent of bald spots.

Wet grass cuttings tend to suppress new buds from growing and as they decompose, they can “burn” the sprouting grass beneath. A heavy layer of mulch on the other hand inhibits the circulation of air and suffocates the shooting grass from underground.

What Happens if There are Too Much Grass Clippings on Your Lawn?

I have already mentioned that too much grass clippings can be detrimental to the health of your lawn. Let’s look into this a bit deeper!

Too many grass cuttings on the lawn exert a lot of weight on the grass blades and this may cause them to break or decay before their wounds heal. The decomposing clippings attract insects making the grass prone to insect and disease infestation.

The green leaves on the grass blades require energy from the sun and adequate air to manufacture their food. If they are covered by a heavy layer of clippings, they will not get enough energy for photosynthesis. This will weaken the stems and cause breakage in the long run. 

Also, the decomposing clippings can cause loss of color in the grass leaves hence affecting the rate of photosynthesis.

The clippings can mat on the surface of soil blocking airflow and causing deformation of the grass stems. They also compress the turf and interfere with root growth and aeration.

Lastly, too many clippings are unattractive and make the lawn look untidy. They can also harbor dangerous animals like snakes.

Can Grass Clippings Cause Grass to Grow on Flower Beds?

Normally, grass clippings do not cause grass to grow on flower beds especially if you mow your lawn regularly and mulch with dry clippings. However, there are several cases where grass clippings CAN cause grass growth in flower beds:

  • If your lawn has overgrown grass with seeds, the seeds will germinate while the clippings supply the soil with nutrients and maintain a favorable temperature for the seedlings to thrive. Also, if the clippings are mixed with grass seeds from the cut grass, they will germinate. This is common in bluegrass and ryegrass.
  • Some grass breeds like creeping bentgrass and buffalo grass have runners which develop roots from clippings and start growing horizontally as they develop new shoots. This is common in overgrown lawns where the grass is cut with runners.
  • Some grass breeds like Bermuda grass develop roots from stolons running on the surface of the soil.  The topsoil in a flower bed is loose and the growing roots penetrate the soil causing the grass to thrive.
  • Some grass node cuttings grow roots that absorb nutrients from the decaying clippings and develop into new shoots. St Augustine grass is a common example.

Warm and humid weather is also ideal for this to happen. In the case of runners and stolons, they can only grow grass if you trim them less frequently making their stems mature before cutting.

To prevent grass clippings from growing grass on flower beds, you should mow your lawn frequently and use dry clippings for mulching flower beds. Grass trimmed regularly will not have many seeds. Runners and stolons cannot grow roots when dry and therefore will not cause the grass to grow. Using dry clippings is the best way to minimize frequent weeding on your flower bed.

Do Grass Clippings Cause Weeds?

Grass clippings do not cause weeds, on the contrary, they suppress and kill weeds. 

If the weeds on your garden or lawn are still young, applying a layer of mulch from grass clippings will smother them and hinder further growth. A deep layer of freshly cut clippings produces a lot of heat which burns and kills the weeds. 

Moreover, if the weeds have grown leaves, the clippings interfere with the air and sunlight energy supply to the weeds causing them to decompose along with the cuttings. 

Note that clippings can only kill and suppress young sparsely populated weeds on your garden or lawn. 

If the weeds are already mature, killing them with grass cuttings is difficult. As the mowing machine throws out the weed cuttings, it aids in the spread of the seeds over a wider area.  This may result in germination and growth of weeds in areas of the garden that were previously weed-free.

If you collect clippings from your lawn after mowing and use them for mulching your seedbed or kitchen garden, you may carry some weed seeds along with the cuttings. The seeds then spread to your garden and germinate under the protection and nutrient supply from the grass cuttings.

Peter Toth

Hi! I'm Peter, the owner of BackyardGadget. Working around the house has always been a big part of my life. I've created this site to share my experience, and to help people choose the right tools for the job. Thank you for stopping by!

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