Lawn Management During Drought

An ariel look down on two men talking on a shady, deep green home lawn
A UF researcher discusses NUF-76, a new St. Augustinegrass variety, with a homeowner. This grass grows more slowly than other varieties, which researchers expect will result in less-frequent mowing. Photo: UF/IFAS

Florida homeowners can maintain healthy lawns during times of drought or water shortage, even when water management districts (WMDs) have imposed mandatory water restrictions. Most turf damage is actually caused by over-watering, and, in general, watering restrictions provide for sufficient irrigation of most lawngrasses. Here are some simple maintenance practices you can use to help your lawn best survive periods of drought.

Mow High

Grass grows more slowly when there’s less water available. So you’ll typically mow less during a drought or water shortage. When you do mow, always mow at the highest recommended height for your grass species. Never remove more than one-third of the leaf blade at any one mowing, as this will stress the drought-stressed grass further. Higher mowing encourages deeper rooting, one of the key mechanisms of drought tolerance.

Sharpen Mower Blades

Sharp mower blades make a clean cut on the grass. These cuts heal faster and stress the grass less than a cut made with a dull blade. Mow your lawn when the grass is dry, so that cut grass does not stick to the mower blade and prevent it from making the cleanest possible cut.

Water the Right Amount

In many cases, lawns can survive when prolonged droughts occur on irrigation of only one to two days per week, if 1/2 to 3/4 inches of water is applied each time. But water only when you see signs of turf wilt — leaf blades are folded in half lengthwise, grass takes on a blue-gray tint, and footprints or tire tracks remain visible on the grass long after they’ve been made.

Never irrigate to the point of runoff. Runoff is water that the roots cannot absorb, which runs into storm drains and eventually into streams, lakes, and other bodies of water, or into groundwater, where our drinking water comes from. Runoff can carry lawn and roadway chemicals and pollutants, and wastes water.

Irrigation run times should rarely exceed 60 minutes for rotary sprinklers and impact sprinklers, or 20 minutes for spray heads. If irrigation run times exceed these guidelines, be sure your system is not applying more than 3/4 inches of water during a single watering.

Water Uniformly

Some irrigation systems are improperly designed and don’t distribute irrigation water evenly. The dry areas they can create (parts of the lawn not receiving enough water) are especially obvious during a drought, when rainfall isn’t masking the problem. Place shallow cans in the bad and good areas of your lawn to determine how evenly your system is distributing water.

If your system is not applying water uniformly, contact a qualified irrigation contractor to make any necessary repairs, or try turning or unclogging the sprinkler heads.

Water Early in the Morning

Irrigate early in the morning, preferably between 4 a.m. and 8 a.m., so that grass blades will dry off quickly at sunrise. Extended wet periods can cause turf disease, so watering late in the day or at night is not a good idea. Irrigating between 10 a.m. and 4 p.m. is not recommended. This will waste water, because the water will evaporate before it can soak into the soil and be absorbed by the roots.

Postpone or Reduce Fertilizer Applications

Grass is more stressed during droughts and water shortages. The last thing you want your grass to do under water management restrictions is to grow more. Hold off on the fertilization until the drought or water shortage has passed. Take note that many fertilizers have a high salt content that can “burn” grass. Some homeowners choose to apply a soluble iron formula to “green up” their lawn, but the resulting color will not last long.

Lawn care professionals have a wider selection of fertilizer materials and application methods available to them than the average homeowner, and they may continue to apply fertilizers at low rates through a dry period.

Postpone Herbicide Applications

Herbicides—weed killers—can stress a healthy lawn even at the best of times. During a drought or water shortage, that stress can limit turf health and reduce the turf’s ability to compete with weeds. So put off your herbicide applications until the drought or water shortage is over.

Spot-treat Lawn Pests, Only if Needed

Pesticides—chemicals that fight insects and other pests—should be applied only as needed. Spot-treat affected areas, not the entire lawn. These chemicals can damage drought-stressed grass. Always make sure you know what pest you have before embarking on a treatment plan, and always follow label directions. The label is the law.

Consider Using a More Drought-tolerant Turf Species

Bahiagrass and centipedegrass have better drought tolerance than other turfgrasses. Although these grasses may turn brown during a drought, they are more likely to resume growth and turn green again when rain or irrigation resume.

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