Handling residual material after mowing directly affects turf health and yard maintenance time. Understanding the composition and decomposition mechanics of grass clippings helps homeowners choose the most beneficial and efficient option for their lawn. This organic material can either be recycled back into the lawn or repurposed elsewhere.
Grasscycling: Leaving Clippings on the Lawn
Grasscycling is the practice of leaving small clippings on the lawn surface, allowing them to quickly decompose and return valuable nutrients to the soil. This technique acts as a natural, slow-release fertilizer. Clippings are roughly 80% water and break down rapidly without contributing to thatch buildup. The process can reduce the need for commercial nitrogen fertilizer by 15% to 20%, as the clippings are a rich source of nitrogen.
Successful grasscycling relies on proper mowing technique, specifically the “one-third rule.” This rule dictates that no more than one-third of the grass blade height should be removed in a single cut. Keeping the grass relatively short ensures clippings are small enough to filter down to the soil surface for quick processing by microorganisms. A sharp mower blade is also important, as a clean cut promotes faster healing and allows clippings to be finely shredded for quicker decomposition.
Mowing only when the grass is dry is another factor for effective grasscycling. Wet grass tends to clump together, forming heavy mats that smother the turf and impede sunlight and airflow. Using a mulching mower, which cuts and recuts the clippings into tiny pieces, is beneficial but not necessary for success. Following these steps ensures the clippings become an invisible, nutrient-rich layer that improves soil structure and supports microbial activity.
When Collection is Necessary
While grasscycling is the preferred method for lawn health, collection via bagging or raking is sometimes necessary. Primary reasons for collection include preventing disease spread, managing excessive grass length, or satisfying aesthetic preferences.
If the lawn is infected with a fungal disease, such as brown patch, dollar spot, or rust, the clippings must be removed. These diseases spread through spores carried on the grass blades. Leaving infected material on the lawn can reintroduce the pathogen or spread it to healthy areas. It is also advisable to clean mower blades after cutting a diseased area to prevent cross-contamination.
Collection is also necessary when the grass has grown too long between mowings, making it impossible to follow the one-third rule. Cutting excessively tall grass results in a heavy volume of clippings that will mat down and smother the underlying turf. Finally, some homeowners collect clippings simply for a pristine appearance, as visible remnants may be considered unsightly until they break down.
Utilizing Collected Grass
Collected clippings represent a versatile, nutrient-dense organic resource that can be used elsewhere in the yard. The high nitrogen content of fresh grass clippings makes them an excellent addition to a compost pile.
When composting, grass clippings are considered a “green” material and must be mixed with “brown” materials, such as dried leaves or shredded cardboard. Layering thin amounts of clippings with brown material prevents them from compacting into a dense, slimy mass that lacks oxygen and produces foul odors. This proper balance ensures aerobic decomposition, where the high nitrogen accelerates the breakdown of the entire batch.
Dried grass clippings can also be used as an effective mulch in vegetable gardens or around trees and shrubs. As a mulch, the clippings help suppress weeds, moderate soil temperature, and conserve moisture by reducing evaporation. Apply the clippings in a thin layer, ideally no more than one to two inches deep. Thick layers can mat together and block the exchange of air and water with the soil.
Handling Excess or Clumped Clippings
Sometimes grasscycling fails, resulting in heavy, unsightly clumps sitting on the lawn surface. These clumps are detrimental to turf health because they shade and smother the grass beneath, causing it to turn yellow or brown. Addressing these heavy deposits quickly prevents lasting damage to the turf.
The simplest solution for small clumps is to use a leaf blower or a lightweight fan rake to disperse the material. Spreading the clumps into a thin layer allows them to dry and settle into the turf canopy, where they decompose as intended.
A quick second pass with the lawnmower can also be effective, especially if the mower deck is raised slightly higher than the original cutting height. The mower’s suction and blade action will chop the heavy material into finer pieces and scatter them more evenly. If the clumping is severe, the material must be raked up and removed to protect the underlying grass.