Summary
The purpose of this report is to educate the average home owner on the potential damage he or she is doing to the lawn. There are three main benefits of having a sharp lawnmower blade: Reduce fuel consumption, Increase the health of the lawn, and decrease time requirements to mow the lawn. How to sharpen the lawnmower blade is beyond the scope of this research but details on how to sharpen a lawn mower blade will be provided in another part of the lawn care tips section. Armed with knowledge of having a sharp blade a home owner can take steps to insure he doesn’t waste money or fuel when cutting his lawn and make sure the health of the lawn is a priority.
After WWII there was a demographic shift towards living in suburban areas in North America. With this shift turf grasses, an ideal ground cover, for these expanding developments flourished. This rich oxygen producing plant comes with an increase in maintenance responsibilities of home owners. The modern lawnmower has made a time intense chore of maintaining grass height easier. However To fully obtain all the benefits of a lawn mower one must keep it in good repair, in specific, to have a sharp blade. The benefits of having a sharp lawnmower blade will be discussed in the following in strike of addressing the problem that most lawnmower owners don’t sharpen their lawnmower blade. Having a sharp lawnmower blade decreases fuel consumption, increases the Health of the lawn, and decreases time require to cut the grass.
Fuel requirements
A lawn mower with a sharp blade will consume 22% less fuel then a lawn mower with a dull blade (steinegger, 2011). According to Dr. Don Steinegger, who researches turf grass at the University of Nebraska. Dr Steninegger brought this alarming fact to the public’s attention on an online journal article. The increased fuel consumption can be explained by a dull blades increased resistance while cutting the lawn. A blunt blade has a larger surface area that is contacting the grass, when you increase the contact area you increase the resistance the engine has to over come to turn the blade. The excessive resistance is what decreases fuel economy. This added stress to the lawn mowers power shaft main bearing decreases the lawnmower life as well, over time of course. The price at the fuel pump today is $1.29/L. This means that for every liter of fuel you burn cutting your lawn you are wasting $0.28. On top of the obvious economic reason, it is inherent to say that this will help decrease your carbon foot print. On average people mow their lawns every ten days ( GreenEdge lawn care, 2011). Over a season these carbon emissions add up. If the mower is electric the principal of higher energy consumption with dull blades still applies. If a home owner spent the time required to sharpen his lawnmower blade he could reduce his carbon foot print and save money.
Health of your lawn
Having a dull lawn mower blade is about the worst thing you can do to your lawn. “A dull blade tears the grass instead of cutting it” (Henkenius, 2005). Up close this excessive damage turns the green grass blade tips yellow. The grass tips are frayed having a look similar to that of torn fabric. From a distance the whole lawn has a brownish-tinge to it and can appear uneven (greenedge lawn care, 2011). It is clearly evident that a dull blade reduces the look and quality of the work done by a lawn mower. Shredded grass tips increases internal surface area exposed. “Researchers found that dull blades increased disease susceptibility, which is consistent with other research findings. Presumably, this was due to greater pathogen entry sites in the shredded leaf tips” (steinegger, 2011). This slows its growth and makes the lawn more susceptible to disease and weed infestation. “The recovery period can be up to three times longer if the grass is cut with a dull blade” (Blackwell, 2011). This just goes to show the extent of the damage a dull blade dose to the lawn. A disadvantage of this slower recovery time is that the lawn is susceptible to weed infiltration. The longer recovery slows root growth which intern leaves room for dandelions to grow. Once you get this problem it can be very difficult to remove these weeds and a herbicide is then required. This is both costly and bad for the environment.
Time requirements for lawn care
Maintaining a lawn requires a fair amount of time. The time spent mowing a yard is related to several variables: quality of lawnmower, maintenance of lawnmower, size of yard, blade sharpness, and grass blade density of the lawn. The time requirement can quickly increase if using a dull blade. If the blade is dull the grass is torn not cut, this process releases excess internal grass mater which is sticky in nature. This excess accumulation sticks to the under side of the lawn mower which decreases the volume under the deck. “As the volume under the lawn mowers deck decreases its ability to dispense the clippings is severely reduced as the vacuum created by the spinning blade is not optimal. If the lawn mower is unable to create a vacuum effect the clippings are not dispensed and get cut over and over resulting in a grass paste” (Blackwell, 2011). This grass paste is left on the lawn behind the mower in large clumps. Because of this the operator must pick these clumps up by hand or go over that section of lawn again. This results in a longer time requirement to cut the lawn. The reduction in volume under the lawn mower also reduces the mowers ability to dispense the clippings into the attached bag. The full capacity of the bag is unable to be used under these circumstances which increase the frequency of emptying the lawn mowers bag. This inevitably slows down the entire process of mowing the lawn. By using a sharp blade on a lawn mower chlorophyll and other grass juices are reduced so the clippings will remain dry and dispense easily while reducing build-up under the mower.
Not having a sharp blade triggers a chain of events that increases the overall time and ware on the lawn mower. This also results in an unpleasant experience for the operator and in some instances the operator will purchase a new mower to solve this issue instead of simply sharpening the blade.
The use of turf grass to cover a yard is a popular choice by many home owners. It also has many environmental advantages. But if the home owner is unaware of the importance of having a sharp blade on the lawn mower the excessive maintenance experienced by the owner may turn the home owner away from wanting a lawn, when all it takes to have a good experience mowing the lawn is a sharp blade. Decreased fuel consumption which saves money and helps reduce your carbon foot print is direct results of having a sharp blade. To avoid having weeds or a visually unappealing lawn sharpen the blade of your lawn mower once a month, the direct health benefits to the lawn are easily noticeable. The chain of events unleashed by having a dull lawn mower blade can hinder the enjoyment of cutting a lawn but also increase the time requirement of this chore. Many home owners enjoy the chore of lawn maintenance as it can be easy if you are armed with knowing the benefits of having a sharp lawn mower blade. Stay active by cutting your lawn and enjoy doing it with a sharp blade.
Recommendations
To ensure ease in maintaining a lawn, sharpening the lawn mower blade is recommended at least once a year. To further the benefits of having a sharp blade check the status of the blade after every month of use. If it is dull get it sharpened. Several methods are available to sharpen a lawn mower blade and could be done with tools around the house. See appendix A for detailed instructions on how to sharpen a blade. If a home owner feels uncomfortable sharpening the blade then the lawn mower can be taken to a small engine repair shop to get the blade sharpened. The cost is between five to fifteen dollars to get the blade sharpened. Or sell your mower and hire a reputable lawn maintenance company to care for your lawn.
References:
Dr. Don Steinegger, NebraskaUniversity, accessed march 24, 2011,http://grounds-mag.com/mag/grounds_maintenance_research_update_sharp/
GreenEdge Lawn Care , accessed march 24, 2011. online:http://www.greenedge-lawncare.com/
Henkenius, Merle”lawn mower tune up”: An hour a year will keep your walk-behind running right. Popular Mechanics(2005).Online: http://www.popularmechanics.com/home/improvement/lawn-garden/1645086
Jeff Karr P.Eng.
Owner/Operator
Greenedge Lawncare Inc.
403-608-1995
