Using Grass Clippings


The question about if you can use grass clippings as a mulch is very common. Grass clippings can be a great way to add a little mulch to your garden, it is organic matter and will add benefits to the garden if used properly, but there are things to watch out for.


Understanding the basic function of mulching is very important when choosing a mulch.

  • When applied properly it conserves moisture from both rainfall and other watering practices.
  • You need a mulch that won’t mat down and shed water, it needs to be a loose, course texture and a structure to allow water to penetrate through to get to the soil.
  • It also needs to be able to maintain a thickness of about three inches without matting to be effective. A three inch layer of mulch is a good thickness to apply for weed suppression along with serving as an insulator to keep the garden soil warmer in the cold weather and cooler in the hot seasons to protect the root system of especially shallow rooted plants.

Organic mulches are a beneficial mulch to use because of there ability to add nutrients back into the soil as they decay, along with helping to improve the soils structure by creating an environment for the organisms that are beneficial to your gardens soil to survive.


Grass Clippings

  • Mowing a lawn at the proper height, 2/12 inches to 3 1/2 inches in with cool season grass and 1 1/2 to 2 1/2 inches for warm weather grass and mowing frequently by only cutting one third of the grass plants total height with a mulching blade on the lawnmower will allow the clippings to be fine enough to decompose in place.
  • By allowing these clippings to decompose in place they will add nutrients back into the soil for your grass to benefit from.
  • Grass clippings alone will provide about twenty five percent of the nutrients that grass needs alone, they contain about four percent nitrogen, two percent potassium and one percent phosphorus.

Possible Problems

  • The first concern is contamination from insecticides, weed killers and other chemical fertilizers, especially if they have been applied to the grass within a three week period of when you want to use them. There are insecticides that are not to be applied to vegetable plants.
  • Compaction is another problem with grass clippings. They tend to compact tightly and get soggy. They don’t have a loose structure to allow for water to penetrate to the soil easily.
  • When applied in a thick layer, grass clippings will heat up during the process of decomposing. This can damage the root system of certain plants, change the soil temperature that can lead to poor plant growth, and the possibility of disease development.