Grasscycling is the natural recycling of grass by leaving clippings on the lawn when mowing. Grass clippings contain moisture, valuable nutrients, and decompose quickly. Grasscycling saves time and money and helps the environment. Mowing time is reduced since bagging and disposal of clippings is eliminated. Grass clippings add valuable nutrients and organic matter to the soil and produce healthy, green lawns. Grasscycling reduces turf grass fertilizer and water requirements, which minimize chemical runoff from entering storm drains and polluting creeks, rivers, and lakes.
Grass clippings make up a surprisingly large portion of California’s waste stream. Much of this valuable green material goes into landfills instead of being reused in our urban landscapes. California lawns can generate approximately 300 to 400 pounds of grass clippings per 1000 square feet annually, depending on turf variety, environmental conditions, and turf management practices. This amounts to 6 1/2 tons per acre each year. Grass clippings are too valuable to throw away, and grasscycling allows reuse of this green material in our urban landscapes If a lawn is properly mowed, watered, and fertilized, grasscycling can actually produce a healthier-looking lawn.
Tips for Successful GrassCycling
Proper mowing, watering, and fertilizing practices result in more moderate turf growth, yet still produce a healthy, green lawn. Grasscycling can be practiced on any healthy lawn by following these turf management guidelines:
Proper mowing is required for successful grasscycling. It is best to cut grass when the surface is dry, and keep mower blades sharp (dull blades can shred grass and create a potential entryway for disease). Follow the “1/3 rule:” mow the lawn often enough so that no more than 1/3 of the length of the grass blade is removed in any one mowing. Proper mowing will produce short clippings that will not cover up the grass surface. You may have to cut the lawn more frequently, or double cut, when the lawn is growing fast, such as in the spring, but cut much less when the turf is growing slowly. If a lawn is not cut frequently enough and long clippings are left on the lawn, it may produce a “hay-like” look which can be unsightly. In many areas of California, raising the mowing height in the summer encourages deeper roots and protects grass from drought and heat damage. The chart below is a recommended guide for mowing heights of common California turfgrasses.
Mowing Heights for Common California Turf Grasses
|Grass Type||Mower Setting (inches)||Mow when grass is (inches)|
|Bentgrass||1/2 - 1||3/4 - 1 1/2|
|Bermuda grass (common)||1 - 1 1/2||1 1/2 - 2 1/4|
|Bermuda grass (hybrid)||1/2 - 1||3/4 - 1 1/2|
|Kentucky Bluegrass||1 1/2 - 2 1/2||2 1/4 - 3 3/4|
|Kikuyugrass||1 - 1 1/2||1 1/2 - 2 1/4|
|Perennial Ryegrass||1 1/2 - 2 1/2||2 1/4 - 3 3/4|
|St Augustine||1 - 2||1 1/2 - 1 1/2|
|Tall Fescue||1 1/2 - 3||2 1/4 - 4 1/2|
|Zoysia||1/2 - 1 1/2||1/2 1 1/2 - 2 1/4|
You can grasscycle with most any mower. Refer to your owner’s manual or contact a local lawnmower dealer to learn if you can safely grasscycle with your existing mower. You may need to purchase a retrofit kit, and your mower dealer can assist you in selecting the correct one. Mulching or recycling mowers make grasscycling easy by cutting grass blades into small pieces and forcing them into the soil. You may also want to consider purchasing an electric mulching mower to reduce air pollution.
Turf grasses vary in their need for water. Most grasses in California need about 1 inch of water every 5 to 7 days in the growing season and much less during slow growth months. Lawns watered too frequently tend to develop shallow root systems, which may make them more susceptible to stress and disease. Deep, infrequent watering produces a deeper, extensive root system which enables turf to resist disease and stress. Over-watering not only is wasteful, it also causes lawns to grow faster and requires more mowing. The best time to water is early in the morning, as less water is lost due to evaporation. Try to avoid watering in the evening because prolonged damp conditions may encourage disease development.
Check your irrigation systems regularly to avoid water runoff or over-spraying, especially if the lawn is on a slope. Look for broken, tilted, or clogged sprinkler heads, and adjust sprinkler heads to ensure even coverage. Remember to change your irrigation timer seasonally to match the water needs of the turf. Contact your local water agency for information and assistance on irrigation scheduling.
Proper fertilization is essential in maintaining a healthy lawn. However, over-fertilization can weaken a lawn by causing excessive and succulent top growth. For moderate, even growth, use a combination of fast acting fertilizers (ammonium nitrate, ammonium sulfate, or urea) and slow release nitrogen sources such as sulfur-coated urea, urea formaldehyde, IBDU or organic fertilizers. Avoid using large quantities of fast acting fertilizers. These fertilizers produce very fast growth for short periods.
Check with your local University of California Extension Office to determine the fertilization rates for your grass type. Regardless of the grass type and its fertility needs, as a general rule, it is better for the lawn to apply smaller quantities of fertilizer more frequently rather than larger amounts less frequently.
Disease & Thatch
Improper watering and fertilizing are the primary cause of spreading disease. If an accommodating environment for turfgrass disease is present, infestation will occur whether clippings are collected or not.
Research has shown that grass roots are the primary cause of thatch, not grass clippings. Thatch is composed mainly of roots, stems, rhizomes, crowns, and stolons. These plant materials contain large amounts of lignin and decompose slowly. Grass clippings are approximately 80-85 percent water, have only small amounts of lignin, and decompose rapidly. Some grasses such as Bermuda grass and kikuyugrass are more thatch-prone than others.
A small amount of thatch (approximately 1/2 inch) is actually beneficial to a lawn, providing insulation to roots and serving as a mulch to prevent excessive water evaporation and soil compaction. It may also create a cushioning effect for lawn play.
Grasscycling is not feasible in every situation. Prolonged wet weather, mechanical breakdown of mowers, or infrequent mowing are situations where grass clippings should probably be bagged since an excessive volume of clippings may be generated. Rather than disposing of collected grass clippings, consider using them in a home or community compost pile. This ‘green’ material can be an excellent addition to compost pile when managed correctly and used in combination with ‘brown’ materials. Clippings decompose quickly, provide moisture, and nitrogen. Let clippings dry before adding them to a compost pile, layer between other materials, and aerate the pile frequently.
Clippings can also be used as mulch to provide weed control and prevent moisture loss around flower beds, trees, and shrubs. Mulching with clippings should be avoided, however, if they are of an invasive variety, such as Bermuda grass, or if herbicides have been applied recently to the lawn.