Yes, that is what David Chalmers of the Virginia Tech Department of Crop and Soil Environmental Services says. When I started taking care of my beautiful new sod lawn, I wanted it to look neat, so I bagged and bagged and bagged….too big of a lawn to do easily. I did however, save the clippings in a compost area to distribute after they dried. Living in the woods allowed me to store leaves and grass without having to bag it and put it in the landfill — what a waste of good clippings! Some states such as Missouri actually have laws against this.
Part of the reason I write these monthly articles is to educate myself by doing research on lawns. When I realized I could save time by using my zero turn mower on the sod areas, I checked into buying a bagger for it. Whoa, was that expensive! While taking the Master Gardener class, I came to understand that it is actually preferable to leave the grass clippings on the lawn, saving labor and time, but more importantly, promoting a healthy lawn. I hope this article will make all of us better land stewards.
The Environmental Protection Agency (EPA) estimates that yard waste accounts for 18% of refuse that is being dumped into landfills, with 75% of it being grass clippings. It is difficult for municipalities to take on this removal project except with leaves and limbs. Grass clippings decompose quickly and can emit foul odors if not handled correctly, making it difficult to take on as a community.
Thatch
There is a long held belief that leaving clippings on the grass causes a buildup of thatch. Academic research shows this idea is not true. Leaving clippings is actually beneficial for the lawn because clippings can return nutrients and microorganisms back to the soil. Thatch forms when turf roots, stems and leaves are sloughed faster than they can decompose. Grass clippings are nearly 85% water and usually decompose faster than other grass plant parts. Microorganisms and earthworms can digest thatch. If the thatch is excessive (greater than 1/2 inch), this brown, spongy material prevents water and air from penetrating to the grass roots. This buildup is worsened by growth encouragement practices such as applying high rates of fertilization and frequent excessive watering. In addition, poor soil aeration and low soil pH inhibit microbial decomposition. If thatch is a problem, use a vertical mower or power rake, available at your local rental company, to reduce the layer. A vertical mower cuts through the thatch with rotating blades or stiff wire tines. The resulting loose material can be added to your mulch or compost pile.
Mowing
Can any mower mulch the clippings? Yes, any mower can do the job if the lawn is mowed frequently before the grass becomes too long. The clippings must be cut small enough to filter down into the soil. The traditional side discharge mower can be safely adapted by trading the bagger for a part that keeps the chute open safely. Mulching mowers, a type of rotary mower that chops clippings before they fall into the lawn, are a good choice.
Mow when the grass needs it and remove only one-third of the leaf height at one time. This may mean more mowing (about every 5- 6 days) in the spring will be needed; but during our hot summers, the need will decrease to probably every 10 days. Also, keep the mower blades sharp and mow when the grass is dry.
Source of fertilizer
This “grasscycling” technique will provide some nitrogen which is released slowly. It will not produce a “greening up effect” but will help improve the soil’s water holding capacity and fertility. Less time and money spent on the lawn is a good thing! However, this will not substitute for fertilization of warm-season grasses in the fall and cool-season grasses in the summer.
Are there reasons ever to bag the clippings?
- If the lawn is heavily diseased, removing clippings may reduce the diseased organism load
- If the lawn is mowed when wet or excessively long, the clippings will mat together and could damage the lawn under the clumps of clippings.
- If your mower does not have a method to operate without a bagger.
Clippings as mulch or compost
If clippings are too long to leave on the lawn, they can be used for mulch or compost. If you spread them out as mulch, be sure to have only a 1 inch layer and use dry grass. If the grass is wet, try to spread it out to dry. Greater thickness can inhibit the penetration of oxygen and moisture to the soil and foul odors may develop as well as heat.
The same problem can also develop if large amounts of fresh clippings are put in the compost pile all at once. Try mixing clippings with dry leaves at a 1:1 ratio before composting. The nutritional value of grass compost depends on the proportion of grass to a carbon source such as dry leaves. If the compost has more turf grass clippings than dry leaves, it will provide more plant-available nitrogen and phosphorus. Lastly, do not put grass clippings in the compost that have been treated with herbicides within the last 2 weeks prior to the mowing.
6 Reasons to practice “grasscycling”
- It improves lawn quality when we allow the clippings to decay naturally, providing valuable nutrients.
- It saves time and work.
- All lawn mowers can grasscycle.
- Grass clippings are a free source of slow release fertilizer
- There is no need to spend tax dollars on landfilling grass.
- It is a simple, easy opportunity for every homeowner to do something good for the environment.
SOURCES
C.R. Wilson and T. Koski, “Eliminate Grass Clipping Collection,”Colorado State Extension Office, http://www.ext.colostate.edu/pubs/garden/07007.html
Christopher Starbuck, ” Grass Clippings, Compost and Mulch: Questions and Answers,” Missouri Dept of Horticulture, http://extension.missouri.edu/p/G6958
Donald Chalmers , “Mowing to recycle grass clippings: Let the Clips Fall Where They May! ” , Virginia Extension office publication, http://pubs.ext.vt.edu/430/430-402/430-402.html