Question: I heard some people use their grass clippings as a mulch for plants in the garden. Can I use grass clippings as mulch? Why or why not?
- Traci L. (Mattapoisett, MA)
Answer: Using grass clippings as mulch may do more harm than good, so I wouldn’t recommend it.
First, if you’ve used weed killers and fertilizers on your lawn, whatever contaminates remaining on the grass clippings could potentially damage the surrounding plants if you use it as mulch. The same goes for insecticides made for the lawn. There could be residuals on the grass clippings that could contaminate you plants.
Second, for mulch to be effective, it needs to be applied to about 3″ in depth. However, grass clippings compact easily and to the point where it would not be effective. For instance, when fresh grass clippings dry and settle, it will compact to less than a third of its original depth.
Third, even if you apply enough grass clippings, they can still damage surrounding plant roots and stems because of the heat they release when decomposing. Changing the temperature of the soil negatively affects plant development and makes it more susceptible to plant diseases.
And finally, using grass clippings as mulch is not that pretty to look at (a brownish yellow color).