Mowing grass damp from rain or heavy dew often leads to clumping, uneven cutting, and a quickly clogged mower deck. This resistance strains the engine and diminishes the quality of the cut. Understanding the mechanics of this issue is the first step toward preventing it. A combination of precise equipment preparation and adjusted operator technique can significantly improve performance in these challenging conditions. This guide provides steps to ensure a clean, clog-free result when waiting for completely dry conditions is not an option.
Understanding Why Clogging Occurs
The primary cause of clogging is the increased moisture content within the grass blades and on their surface. This added water increases the mass of the clippings, making them too heavy to be fully expelled by the deck’s airflow. Instead of flying freely, the dense clippings immediately lose momentum. This issue is compounded by the sticky, paste-like substance formed when water mixes with chlorophyll released during cutting. This organic paste adheres firmly to the metal deck surfaces, especially around the blade tips and discharge opening, creating friction and disrupting the vacuum effect necessary for lifting the grass.
Essential Mower Preparation and Adjustments
Preparing the equipment is the most effective preventative measure against clogging. Ensure the mower blades are aggressively sharp. A sharp blade cleanly slices the grass with minimal tearing, producing smaller, lighter clippings that are more easily ejected.
The underside of the cutting deck must be completely free of dried, caked-on grass from previous mows. Existing debris creates surface area for new, wet clippings to cling to, accelerating buildup and restricting airflow. Use a scraper or putty knife to remove all old organic matter.
Applying a non-stick coating to the clean deck surface minimizes the adhesion of wet grass. Commercial deck sprays create a slick barrier that repels moisture and organic material. This protective layer forces the wet grass to slide along the deck’s interior rather than sticking and beginning the clumping cycle. Reapply this coating frequently.
Adjusting the cutting height directly impacts performance in wet conditions. Raise the mower deck to its highest or second-highest setting, which improves the volume of air circulating beneath the deck. This higher setting allows greater lift and provides more room for the heavier clippings to circulate. Utilizing the side discharge chute is preferable to mulching or bagging, as both systems are highly susceptible to clogging with high-moisture material.
Operational Techniques for Wet Conditions
The operator’s technique must change significantly to compensate for the resistance created by damp grass. Reduce your forward travel speed compared to dry mowing. Moving slower allows the blades more time to cleanly cut the dense material and ensures the engine maintains maximum blade speed for lift. Pushing the mower too quickly overwhelms the deck’s capacity.
Only cut the upper one-third of the grass blade length during a single pass. Taking off too much height introduces excessive moisture and mass into the deck. This practice reduces the volume of clippings processed, minimizing strain on the engine and the potential for clumping. If the grass is significantly overgrown, complete the task in two separate passes separated by a few hours to allow the cut tips to dry slightly.
Employ a greater overlap on each pass than you would use during dry conditions. Aim to overlap the previously cut strip by about one-third. This technique effectively reduces the width of the cut strip, allowing the mower to handle a smaller volume of wet grass per unit of travel distance. The reduction in cutting width helps maintain the necessary blade tip speed and prevents the engine from bogging down.
The time of day chosen for mowing impacts the moisture level of the grass. The best time to mow is late morning or early afternoon, long after the morning dew has evaporated. Allowing the sun and wind to dry the grass blades drastically reduces the water content of the clippings. Avoid mowing after a heavy rain shower or during active rainfall.
Safe Cleanup and Maintenance After Mowing
If a clog occurs, or before performing any maintenance, follow safety protocols to prevent accidental engine startup. Turn the engine off, wait for all moving parts to stop, and disconnect the spark plug wire. Removing the power source eliminates the possibility of the engine unexpectedly turning over while your hands are near the blades.
Immediate and thorough cleaning of the deck is necessary following any session of mowing wet grass. High moisture content and sticky residue rapidly promote rust and corrosion if left in place. Use a scraper to remove the bulk of the wet material, followed by a stiff brush or hose rinse if supported by your model. Allowing the deck to dry completely before applying a protective spray helps maintain the metal’s integrity and ensures optimal airflow for the next cutting session.