Grasscycling, the practice of leaving cut grass on the lawn after mowing, is generally beneficial for turf health and is a sustainable lawn care strategy. This simple action transforms yard waste into a natural resource that contributes to the vitality of the turf ecosystem. When performed correctly, grasscycling reduces the need for supplemental fertilization and decreases the volume of material sent to landfills. The effectiveness of this process depends on applying proper mowing techniques to ensure the clippings break down quickly and efficiently.
How Grass Clippings Fertilize the Lawn
Grass clippings contain nutrients that the grass plant has absorbed from the soil. Returning these clippings recycles these components, acting as a slow-release natural fertilizer. Soil microorganisms break down the organic material, releasing essential plant nutrients back into the root zone. Clippings are rich in Nitrogen (N), which promotes green, leafy growth, but they also contain Phosphorus (P) and Potassium (K). Research indicates that this natural recycling can supply up to 25% of a lawn’s annual fertilizer requirement.
Because the clippings are roughly 80% to 85% water, they decompose rapidly, typically within a few weeks, which is why they do not contribute to the formation of thatch. This rapid breakdown promotes consistent color and density without the sudden growth surges associated with synthetic fertilizers. This continuous feeding helps maintain a dense turf that naturally resists weed invasion.
Essential Mowing Techniques for Grasscycling
Successful grasscycling relies on cutting the blades into small pieces that can fall easily to the soil surface. The most important guideline is the “one-third rule”: never remove more than one-third of the grass blade’s total height in a single mowing session. This rule ensures the clippings are short enough to settle quickly and not smother the turf beneath.
Mowing frequency must be adjusted to match the growth rate to comply with the one-third rule; rapid growth periods may require mowing every four to five days. Using a sharp mower blade is also important; a dull blade tears the grass, stressing the plant and turning the tips white or brown.
Ideally, a mulching mower is used, as it is designed to circulate the clippings beneath the deck, cutting them multiple times into fine particles. Mow only when the grass is dry, as dry clippings disperse evenly, whereas wet clippings stick together and form undesirable clumps.
Situations When Removing Clippings is Necessary
While grasscycling is the preferred method for lawn maintenance, there are specific conditions that require the removal of clippings to prevent turf damage. The presence of a turf disease, such as a fungal infection like rust or dollar spot, necessitates bagging the clippings. Leaving infected clippings on the lawn can actively spread the fungal spores across the yard, worsening the outbreak.
Another situation demanding removal is when the grass has become excessively long, such as after a vacation or prolonged rain. When too much leaf material is removed at once, the volume of clippings is too great. These heavy, dense layers of clippings will clump on the surface, blocking sunlight and air circulation, which can quickly smother the underlying grass and create dead patches.
Similarly, mowing when the grass is wet causes the clippings to mat together instead of scattering evenly. These wet clumps resist decomposition and encourage the development of localized fungal diseases. In these instances—disease, excessive length, or heavy wetness—it is better to collect and compost the clippings to maintain the overall health of the lawn.