Just Mow It: A Guide to Grass Recycling

Consider the Benefits of Leaving Clippings on the Lawn when Mowing:

• Clippings left on the lawn recycle nutrients, saving about 25% of your annual fertilizer costs. According to Dr. Norman Hummel, Jr., Turfgrass Specialist at Cornell University, "one ton of fresh clippings contains approximately 15 pounds of nitrogen, 2 pounds of phosphorous and 10 pounds of potassium -- the three major nutrients -- and smaller quantities of the other elements essential for plant life." We must stop thinking of grass clippings as "garbage."
• According to a University of Connecticut research scientist, clippings left on the lawn can increase the organic content of the soil and lead to increased earthworm activity. Earthworms improve soil aeration and water movement through the soil, providing a better environment for plant growth.
• A ton of grass clippings contains more than 1,700 pounds of water. Leaving clippings on the lawn saves tax dollars spent for labor, fuel costs and dumping fees that are incurred to dispose of this moisture-laden material.

How To Recycle Grass

Successful recycling of grass clippings to your lawn requires nothing more than basic lawn care on a regular basis. 

• Mow when your grass is dry and 3 to 3-1/2 inches tall. Never cut it shorter then 2 to 2-1/2 inches or remove more than one third of the leaf surface at any one mowing. This will allow your lawn to have a larger and deeper root system -- a stronger defense against weeds, diseases and drought.
• Use a sharp mower blade or a mulching mower if you have one. A sharp blade and frequent mowing will mean finer clippings that will decompose quickly. If you have trouble using your mower without the bagger, call your dealer for assistance. Mulching kits are available to retrofit some mowers.
• If you have thatch in your lawn, use a dethatcher or core aeration machine. A 1/2 to 1 inch layer of thatch is no problem; a thicker layer will keep clippings from reaching the soil.
• Avoid over-fertilizing your lawn. At most, fertilize the lawn in May, September and late November. Remember, the more you fertilize, the more frequently you will have to mow. Slow or controlled release fertilizer sources are preferred.
• Don't over-water. Lawns require about one to two inches of rain or irrigation water a week. If water runs off lawn before one inch of irrigation is applied, turn the sprinkler off, let the water soak in for about a half hour, then continue watering. A can or rain gauge placed in an open area of the lawn can be used to measure amounts of rainfall and irrigation.

Diagnose lawn problems and apply corrective measures when needed. When renovating a lawn, use grass varieties that are resistant to environmental stresses, diseases and certain insects.

When to Recycle Grass

Grass recycling need not be an all or nothing approach to lawn maintenance. You may choose to collect your clippings every third time you mow, every other time or just in the spring and fall. Regardless, you are creating savings for you and the environment. If you want to collect your clippings occasionally, recycle them as a mulch in the garden or in planting beds. They can also be added to the compost pile.

Avoid mulching with grass that has been recently treated with herbicides that can harm your plants. Chemically treated clippings should be left on the lawn or composted where herbicides will break down. Use a mulch only after two months following herbicide application.

When composting, do not use clippings alone. Clippings mat together, depriving the compost microbes of oxygen and cause an odor. It is essential, therefore, to mix grass clippings with leaves in a ratio of three parts leaves to one part grass clippings. Turning the compost pile with a pitchfork every few weeks will add oxygen to the compost and eliminate odors. If you can't use grass clippings in your yard, find a neighbor who might value them as a mulch or compost material.

With collection and disposal costs at a premium, keeping you lawn clippings out of the garbage truck saves money and protects the environment.

Grass Recycling Facts
Do clippings left on the lawn cause thatch?

Research indicates that grass clippings left at mowing do not cause thatch in a lawn. Thatch is the non-decomposed or partially decomposed organic matter that accumulates between the base of actively growing grass plants and the soil surface. A layer of thatch will develop if organic matter is produced faster than it is decomposed by micro-organisms.

However, in a properly maintained lawn, grass clippings decompose rapidly and contribute very little to thatch accumulation. Over- fertilization or letting grass grow too long between mowing are two maintenance factors that frequently result in thatch build up.

Does leaving clippings result in an unsightly appearance?

Frequent mowing of grass when it is dry or using a mulching mower produces short clippings which rapidly disappear. When using a mulching mower, the mowed blades of grass are recut and forced down into the base of the lawn.

If the grass is overly long, collect the clippings and use them as a mulch for your flower or vegetable beds or add them to your compost heap.

Do clippings left on the lawn increase disease problems?

There is no increase in disease problems when clippings are left on the lawn. Improper watering and fertilization practices have a greater influence on the occurrence of disease.

Caring for a lawn can be hard work, and removing lawn clippings is one of the most time consuming, back breaking parts of the job. Why not recycle your grass clippings by leaving them on the lawn when mowing? You would then eliminate the hassles of raking, stopping every few minutes to empty the mower bag and wrestling with expensive trash bags.

In addition, leaving grass clippings saves landfills and incinerators from being overburdened with organic materials that are valuable and completely recyclable!

Some communities have legislation that prohibits yard waste, including grass clippings from being disposed of in landfills or incinerators.

For more information contact: Tom Kowalsick, Extension Educator - Horticulture, CCE - Suffolk County

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