By Charles Marr
Kansas State University
During the many years I have written this column, I have repeated some topics--as certain topics are pertinent to talk about each and every gardening year.
I often wonder if there is a topic that is brand new that I have never discussed before. In looking through my filing system, I think this week will be one of those "first time" discussions--sharpening your lawnmower blade.
Most commercial turfgrass operations, such as parks and golf courses, use a reel-type cutting mechanism on their mowers. This reel blade shears against a metal plate in a scissors-like cutting action that results in a sharp, clean cut to the blades of grass. This sharp, clean cut is vitally important to turfgrass growth and development.
Most of us don't use a reel-type mower, but use a rotary blade mower that cuts by a rapidly turning blade shearing off the grass blades. While commercial turf operations adjust and sharpen their blades on a very regular basis--often daily, in some cases--most of us tend to neglect our lawnmower blade until the sharp edge is well rounded--especially after we have nicked a few stones or other obstructions every now and then.
When turfgrass is lush and green in the early spring, grass blades are mostly water and very tender. However, about this time of year, the grass blades contain more conducting tissues and also seedstalks begin to develop. Seedstalks are round and much tougher than grass blades. When you cut tough grass blades and seedstalks with a dull blade, the cut edges become frayed. This has two distinct disadvantages. First, the cut edges give the lawn a whitish, frayed appearance. In addition, there is a distinct change in the grass growth pattern. Because of more injury to the plant, the grass slows down its growth pattern and root systems don't develop as well or deeply. You might think that slowing down growth is a good thing; however, at this time of year, it is not a good thing to have your grass not develop a deep, aggressive root system to get it through the summer months in good shape.
Many new mowers use a mulching action, where blades of grass are chopped into little pieces and are blown down into the turf, rather than discharged out the side or back through a chute. It is especially important in these mulching mowers to use a sharp blade for some good cutting action, in addition to the things we just talked about.
Now is an excellent time to take a look at your lawnmower's blade. Make sure the spark-plug wire is disconnected before removing the nut (or bolt) holding the blade in place. The blade needs to be sharpened uniformly on both sides. Also, check the balance of the blade after sharpening. Most commercial mower service dealers will automatically do that for you when sharpening your blade. If the blade is badly knocked or damaged, consider replacing the blade with a new one that is readily available from many mower dealers, hardware stores or discount centers--be sure to use the same size blade, since blades differ in width and length.
The result of a sharp blade will be a clean, sharp cut end of the grass blade. This is more healthy for your lawn, gives the lawn a deeper green appearance and makes your mower cut more efficiently and easily. With grass blades beginning to "naturally toughen up" about this time of year, it is an ideal time to get the blade sharpened. Check the blade for sharpness every two to three months of use and make sure you keep it sharp throughout the season.