These are basic guidelines for mowing heights. Keep weather conditions (hot, cold, and drought) in mind whenever you mow.

Mowing Height for Cool-season Grasses

  • Bluegrass - 2 to 2 1/2 inches
  • Perennial Ryegrass - 2 to 3 inches
  • Fescue - 3 to 4 inches

Mowing Height for Warm-season Grasses

  • Bermuda - 1 1/2 to 2 inches
  • Zoysia - 1 to 2 inches

While you may have never given much thought to mowing your grass, the following information will help you to avoid harming your lawn.

Remember that mowing is pruning. Proper mowing increases the density of the lawn, which in turn decreases weeds. Each type of grass has a recommended mowing height (see above). Find out which type of grass is in your lawn (you may have more than one) and mow at the proper height.

Stick to the 1/3 Rule

Never remove more than 1/3 of the grass blade length at any one time. A healthy lawn can survive an occasional close cut. Repeated close mowing produces a brown lawn and has several harmful side effects, including the following:

  • Injury to the crown, where new growth generates and nutrients are stored.
  • Reduction of the surface area of the blade, making the blade surface insufficient to produce food through photosynthesis.
  • An increase in the sunlight reaching weed seeds, allowing them to germinate.
  • Risk of soil compaction.

Consistent Tips

  • Mow when the grass is dry. The blades will be upright and less likely to clump when cut.
  • Avoid mowing in the heat of the day to prevent heat stress on the grass and yourself.
  • Keep mower blades sharp and balanced. Ragged cuts made by dull blades increase the chance of disease and pests.
  • Change the mowing pattern each time you mow. Grass develops a grain based on your cutting direction, tending to lean towards the direction you mow. Alternating the pattern causes more upright growth and helps avoid producing ruts in the lawn.
  • Mow moving forward whether you're pushing a walk-behind mower or sitting behind the wheel of a lawn tractor. Not too fast, however, as that can shred the tips of the grass.
  • Discharge the clippings (unless you bag them) toward the area you have already cut.
  • Leave clippings on the lawn unless they form clumps or rows. This technique (known as grass cycling) returns nutrients and nitrogen to the lawn.
  • Consider using a mulching mower or mulching attachments.
  • If you bag your clippings, consider composting them.
  • Mow grass higher in shaded areas under trees. In these areas grass has to compete with tree roots for water and nutrients.
  • Reduce mowing frequency and raise the mowing height of cool-season grasses when hot, dry weather slows their growth rate.
  • Never mow when frost is on the ground.

Mowing New Grass

Newly seeded grass needs three to four weeks to get established after germination before its first mowing. The grass blades are tender and easily damaged, and foot and mower traffic could compact the soil, especially if the soil is moist. Mow when the new grass is 3/4 inch to 1 inch taller than its recommended regular mowing height.

Just as there is a right and wrong way to mow a yard, there is also a right and wrong way to water a yard. In particular, irrigation systems take some finagling to get them right.

Most people with irrigation systems do not understand the best way to program and manage their irrigation system. The tips here will help you figure out how to set your irrigation system, regardless of which system you own.

  • Turfgrass uses the most water during times of high heat and low humidity on breezy afternoons. This tends to be during late April, early May, and from August through October.
  • Turfgrass uses water to cool itself very similarly to how a car uses a water pump. Water is pulled in through the roots and exits through the leaves. When the humidity is below 70%, water is rapidly pulled throughout the plant and into the atmosphere. If enough water is available, the grass will stay green and healthy. If you have a week with no rain, temperatures in the upper 70s to upper 80s, and humidity below 70%, your lawn will use almost 1.5 inches of water. These weeks are rare but do occur during the months listed above.
  • When temperatures are high and the humidity is high, your lawn will use only about 1 inch of water per week. When humidity levels are high, the turf-grass cannot pump the water effectively because the atmosphere is already moist. This is typically when you start to see fungus develop. The best tip is to water each zone just two days a week, applying ½ inch of water to each zone.

In order to figure out how much water each irrigation zone is putting out, place coffee cups or tuna cans in the lawn; make sure these are flat on the bottom with vertical sides. Let the system run however long you have the system currently set. Placer a ruler in the can to determine the amount of water you are applying for the amount of time you have each station set. Adjust the time as necessary to catch half an inch each time the system runs. Set your irrigation system to water twice weekly during most of the year.

During the time of the year when humidity drops, you may have to add a third day of watering to keep the lawn properly hydrated. We use irrigation to supplement rainfall. When nature provides a heavy rain, the water seeps through the profile and the grass responds. The roots of the turfgrass grow downward towards the seeping water. Therefore, the roots grow deep and strong. People, who water for a few minutes several times a week, encourage the roots to stay near the surface because the roots get frequent light water on a consistent basis.

When the average temperature climbs into the 90s for a few days, weaker grass wilts quickly. When the grass wilts or dies, weeds take its place. The second reason for watering deeply and infrequently is as follows.

  • Light, frequent, watering keeps the soil surface damp.
  • This encourages weeds like nutsedge, crabgrass, Johnsongrass, and dallisgrass to grow.
  • The turfgrass gets zero benefit from a wet soil surface.
  • Weeds, however, love a wet soil surface.
  • We want to encourage the turfgrass while discouraging weeds.

Changing your irrigation to water deeply and infrequently will reduce weed germination by 90%. Please try to adjust your system to more closely resemble the deep and infrequent system. If you have a large system with many zones, you may need to water half of your zones one night and the other half of the zones the next night in order to run each zone long enough to apply ½ inch per watering.

The best time to water your lawn is from midnight to 7:00 am. The old wives’ tale of “watering at night causes fungus” is just that, a wives’ tale. Dew forms on turfgrass each night and keeps the leaves wet until the sun dries them the next morning. Turfgrass also excretes guttation water during the night.

Guttation water is high in sugars and excellent for feeding fungal spores. Therefore, irrigation at night washes off guttation water, which is a good thing. Turfgrass fungus occurs more when the duration of leaf wetness increases than when the total amount increases. Water left on the leaf blades when soil temperatures are high is like adding gasoline to a fire for fungus. Therefore, we need to stop watering by 7:00 am, so that the grass blades will be dry by the same time they would if it were only dew on the leaf blades. High air temperature + high leaf moisture=fungus development!

Take a Phillips head screwdriver and stick it in the ground. You should be able to push the screwdriver in the ground and touch the handle of the screwdriver to the soil (as far as it will go and making sure, of course, that you’re not in the area of utility lines). If you can, and the screwdriver does not come out of the ground muddy, your soil is perfect. If the screwdriver slides in the ground very easily and comes out muddy, reduce the duration time of watering. If you have a hard time and have to stand on the screwdriver to make the handle touch the soil, increase the duration of watering.

Please call The Turf Doctor with any questions about your irrigation habits. With your help, we can give you the healthy, weed free turf you are looking for! Without your help, we can’t make your lawn the best it can be! You can also check out our FAQ page for more information.

For your convenience, we have compiled a short list of trusted local companies that offer additional lawn services you may want to use. We believe these companies to be the best in Middle TN.

Clairborne Landscapes

Plant Health Care & Tree/Shrub Treatment Programs

(615) 799-7979

Keith Burgess

Mole & Wildlife control

(615) 490-7004


Irrigation & Drainage

(615) 207-5841

Sunny Face Lawncare

Landscaping/Hardscaping, Irrigation, & Grading

(615) 372-4739

Major League Lighting

Landscape Lighting

(615) 974-5655

Our Experts Create Lush Lawns

When it comes to cultivating a yard to be proud of, let the experts at The Turf Doctor help. Call (615) 472-8245 or request a free estimate now. We serve the greater Nashville area including Belle Meade, Green Hills, Bellevue, Tennessee, and the surrounding areas.

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