Question: My landscaper said he would no longer be bagging my grass clippings. I am concerned this won't be good for my lawn. What is the correct answer?
Answer: During the summer months 20 percent to 30 percent of residential waste consists of grass clippings. They are traditionally bagged and hauled to a landfill or recycling center. Laws are developing around the country to make it illegal to dispose of them as household waste. Removal of these clippings is expensive, laborious, but most of all a waste of valuable nutrients.
Reasons for bagging your clipping have included some misconceptions. Research shows leaving the clippings on your lawn does not contribute to thatch in the lawn. Thatch develops from non-decomposed or partially decomposed organic matter that accumulates between the base of the actively growing grass and the soil surface. Thatch results when the accumulation of organic matter is faster than the decomposition by micro-organisms.
When your lawn is properly managed, grass clippings decompose rapidly. Too much fertilization and infrequent mowing are two cultural practices that will contribute to thatch. Your lawn should be mowed when it is dry and about 3 inches tall. Wet grass clippings cling to the mower and clump on the lawn. They also do not filter down to the soil surface as well as dry clippings.
Never cut your lawn shorter than 2 to 2 1/2 inches tall. This will help your lawn have a deeper root system to help fight off disease, weeds and drought. Your mower blade should be sharp so finer clippings are made and will decompose quicker. Dull blades rip and tear the grass blades which promotes disease and causes the lawn to have a tan and ragged appearance. Mow every five to six days during the active growing season and every 10 days when growth slows.
If you are keeping your grass clippings you will still need to apply an annual application of fertilizer. Grass clippings contain 2 percent to 5 percent nitrogen that is slowly released and in the long term will increase the water holding capacity and fertility of the soil. This benefit translates to less money spent on fertilizer and water.
A mower specifically designed as a mulching mower is helpful but not required. A side mower will still work but mulching kits are available to refit your mower. Your landscaper is correct and the change to leaving your clippings will benefit you as well as the environment.
Mona Bawgus is a certified master gardener and consumer horticulturist with Rutgers Cooperative Extension of Atlantic County. Write to her c/o Rutgers Cooperative Extension, 6260 Old Harding Highway, Mays Landing, NJ 08330. Email: