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Mowing Practices

Proper Mowing Practices – Stephen Griner (2012)

Lawn mowing is the most fundamental and commonly performed service in all of the lawn maintenance industry. Understanding and utilizing proper mowing practices will yield serious dividends in the way of a lush green lawn and even better, envious neighbors! To maximize the performance of the turf, mowing needs to be performed properly which also includes adjustments to the techniques and frequency according to environmental conditions.

In actuality, mowing is considered a detrimental practice to the health of turfgrass. It reduces carbohydrates in the plant, it creates entry points for disease pathogens and it increases water loss. Considering these facts, you can see how mowing too low or too often during a stressful environment(heat and/or drought) is damaging to your lawn.

The most important aspect of proper mowing practices is using the recommended mowing height range for a lawn’s particular species of turfgrass. Most of the lawns in this region consist of Turf Type Tall Fescue grass. Our recommended mowing height range is 3″ to 3.5″ tall. Mowing at the recommended height will help maximize summer hardiness, keep the weed population down and help fight off disease problems.

Top Five Mowing Tips

  1. Use the recommended height of cut. Higher is better.
  2. Don’t mow more than every other week in the summer months. Unless absolutely necessary.
  3. Return clippings to the turf. Don’t bag them and discard them.
  4. Keep the blades on your mower sharp.
  5. Follow the “1/3 Rule”: No more than 1/3rd of the leaf blade length is removed during any one mowing.

Personally, on my own home lawn, I set my hand mower as high as it will go for 95% of the mowings of the year. Why do I do this? There is a direct relationship between top growth (over the soil) and the total mass of the root system (beneath the soil). In a nutshell, a higher mowing height results in increased root mass which in turn makes the lawn tougher under stressful conditions such as heat, drought and disease.
There is also a basic rule to follow when mowing lawns. It is called the ‘1/3 Rule.’ The lawn should be mowed frequently enough so that no more than 1/3 of the leaf blade length is removed during any one mowing. Following this simple rule will help sustain the plant’s stored carbohydrate reserve in case it needs to be utilized during stressful times.

We at Scientific Plant Service recommend that you always mow your lawn at the recommended height. If you have a lawn service perform your mowing throughout the season, make sure they use the correct mowing height, mow only when necessary in the summer as the lawn is under environmental stress, return the clippings to the turf(not bagging) and keep the blades sharp. Keeping the blades sharp will help to minimize entry points for disease pathogens, minimize water loss, and keep a more uniform color. Keeping the grass tall and minimizing mower traffic/wear during the summer stress period, will give the lawn the best chance to make it through the heat and drought stress in good shape.

If your mowing company can’t make a mowing height change for you, I recommend finding another company that will!! If your mowing company will not skip a weekly mow in the summer when needed because they won’t get paid that week, pay them to pick weeds or water plants and dry spots in the lawn if a weekly visit is required. Ask them how often they sharpen their blades. If they mow several properties daily, this wear will add up and the blades will need to be sharpened more often. These concepts are that important to the health of your lawn.

One last simple concept that homeowners are usually not aware of is winter hardiness. Leaving the grass long over the winter is better for the overall health of the lawn. I do agree that a late season mow gives the lawn a cleaner look heading onto winter, but is this a heathy thing to do for the turf? NO!! Basically, having more carbohydrate reserves(Sound familiar. Reference summer concepts above.) will help grass plants through the winter. If the winter brings extremely cold temperatures, ice or desiccating winds these extra carbohydrate reserves will help the grass plants a great deal.

PROPER MOWING PRACTICES, WHEN/WHEN NOT TO BAG, USE OF MULCH MOWERS

A well groomed lawn is extremely important to the aesthetics of our landscapes and when done properly will maintain its health as well. Most people do not realize that lawn mowing is a science and not a mere chore. Mowing correctly is one of the most critical cultural practices in turf maintenance. When cutting our lawns it is essential to know the variety of grasses we have in order to determine the proper height setting of our mower. Cool season grasses like bluegrass, fine fescues, and tall fescues should be cut at about 3 inches. This helps to reduce crabgrass and broadleaf weed germination by shading out their seeds. Cropping too closely may cause more disease problems, added stress during hot and dry periods of summer, and greater susceptibility to traffic injury. Close mowing also hampers root development which results in weaker turf. Warm season grasses such as zoyzia and bermudagrass should be mowed much shorter to about .5 to 1 inch. These creeping stoloniferous grasses have much lower photosynthetic surfaces so they tolerate much lower mowing which in turn slows thatch buildup.

Grass must be mowed frequently enough so that no more than 1/3 of the grass blade is removed. Cutting too much at once results in scalping, weakened turf, poor appearance, and excessive clippings smother and reduce light to lawn and must be removed in order to prevent creation of more thatch. A light thatch layer (1/4-1/2″) is beneficial for moisture retention and increased wear tolerance; whereas too much thatch results in shallow roots, more disease and insect problems, restricts movement of water, air and nutrients into soil, and makes the lawn more susceptible to scalping due to uneven thatch depth. Normally, it is advisable to leave the clippings to recycle the nutrients back into the turf; but disease problems, heavy thatch, and zoyziagrass due to its slow blade decomposition may require you to bag the grass. If you must collect the clippings, make the effort to compost and use them on your garden rather then sending this recyclable material off to burden our landfills. Studies have shown that 20% of the country’s landfill space is comprised of lawn clippings resulting in many states and municipalities now banning them from their landfills. Mulching mowers are becoming more popular because they are specially designed to finely chop the blades, thus increasing the rate of decomposition and eliminating the need for bagging.

Other important mowing tips:

Alternate mowing patterns to prevent compaction and uneven wear.

Keep mower blades sharp to avoid shredding and bruising of grass plants.

Cut according to the growth rate, not the calendar! Using the 1/3 rule means mowing at least once or twice a week in spring and fall and normally much less in summer.

If you miss a mowing and grass becomes too tall raise the blade height to avoid scalping and gradually lower blades to desired height with subsequent mowings.