Growing things deplete the nitrogen and other nutrients in soil. Crop rotation was implemented just to offset the reduction in nutrients. Plants use nutrients at various levels. For example, corn uses a lot of nitrogen in a growing season, but soybeans and alfalfa process and store nitrogen in the roots. Farmers in the corn belt will sometimes plant soybeans two years in a row on ground that grew corn for one year.
For lawns, the same sort depletion of nutrients occurs. Homeowners can buy fertilizer to replace the nitrogen, phosphorous and potassium when the lawn needs nutrients. Lawns with the clippings left on them need 25 to 30% less fertilizer applications according to university studies in Missouri and elsewhere.
Some people rake their lawns or use bag mowers, many because they don't know why they are doing it. Bagging grass clippings is recommended where the type of grass tends to create a thick thatch. Thatch is bad, because it smothers the grass, restricting air and water flow. This does not apply to the vast majority of lawns, particularly those with fescue and ryegrass. Ryegrass is very good at returning nutrients to the soil.
If the grass clippings must be removed from the lawn, other methods of recycling are available. Home composting, commercial composting and using the clippings as mulch or soil additives in flower beds are all good suggestions. Clippings can be placed in a one inch thick layer in plant beds but should not touch trunks or stems of plants and trees.
What is in the Grass Clippings?
Grass clippings are about 4% nitrogen, 0.5% phosphorous and 2% potassium. Approximately 85% of the clippings is water. Remove the clippings and the grass is lacking a source of nutrients and water. A study from the University of Connecticut found that nitrogen from grass clippings began showing up in grass within two weeks. Over a three-year period, one third of the nitrogen in the grass clippings was found to be utilized by the remaining grass.
Cost and Space Savings
The cost of watering grass in mid-summer and applications of fertilizer monthly, recommended by some, can be a budget-buster. Bagging up grass clippings for curbside pick up can also be pricey if payment is required to haul it away, even if municipalities will haul it away which some will not.
About half the states have banned the deposit of lawn clippings and other yard waste in landfills. In the summer, lawn and yard waste can be as much as half the weight of the trash thrown in a landfill, and the waste of nutrients and water in the landfill disposal is not the only drawback. Ground water contamination with nitrogen and other elements is produced by just such materials in the landfill.
Removing clippings looks to be a waste of both effort and money. The best approach is to leave them on the lawn. Using a mulching mower is good, but simply removing the bag on the mower (and installing any necessary safety guards) will also work. Mow when the grass is three to four inches high, or mow longer grass twice, once with the deck high and once with it at the desired height.
Leaving the clippings will seem like a vacation to the habitual bagger, but it is a vacation that pays back instead of costing money.
- Resources:
- Calaveras County Extension, University of California, Recycle Your Grass Clippings
- NYC Compost Project, Lawn Care for Homeowners
Eilene Toppin Ording - Eilene Toppin Ording comes from a wide industrial and educational background. A farmer's daughter from Minnesota, Eilene is an active ...
