Studies have shown that the climate in Minnesota makes watering your lawn optional in normal years. The type of grass, its age and condition, and your personal expectations are all factors that need to be considered when deciding whether or not to water.
If a lush, green lawn is important to you, watering is necessary in all but the wettest summers. Be aware of your city’s watering guidelines and follow them. Watering will also be necessary if your lawn has been newly seeded or sodded, or if it is recovering from insect problems, disease, or heavy weed damage. High traffic areas, such as children’s play spaces may also require watering.
Knowing what type of grass you have will help you plan a watering regimen. Kentucky Bluegrass usually goes semi-dormant during hot, dry weather. It will turn brown but becomes green again when sufficient rain falls. Fescue is very drought tolerant, but will grow very slowly during dry weather. The “elite” varieties of Bluegrass aren’t as tolerant and will probably need supplemental watering during dry weather. No grass should be expected to survive an extreme drought without watering.
Lawns need about 1” of water per week. If Mother Nature does not provide, operate a sprinkler for 3.5 to 4 hours per area weekly. Keep the interval between waterings as long as possible without subjecting the grass to too much stress. This will help develop a good, deep root system. Frequent, light waterings cause shallow rooting and may lead to a weak lawn which is susceptible to weeds and disease.
Some areas of the lawn dry out faster than others. Southern exposures, high sun areas, high traffic areas, and slopes may need extra attention.
To make sure you are watering evenly over a particular area, take several same-sized, straight-sided, empty cans (i.e., tuna fish cans) and space them at regular intervals in the lawn. After watering, check the cans to see if they are equally full. This is also a way to test how many inches of water your sprinklers apply in a given time. Most sprinklers apply about 1/4” per hour.
The most efficient time to water is very early morning as less water will evaporate at that time. Midday watering is fine for grass, although more water will be lost to evaporation and wind. Avoid watering so late in the day that the grass is wet after dark. Turf diseases thrive in wet, cool grass.
There are two basic types of sprinklers to choose from - oscillating or impulse. Oscillating sprinklers cover a square or rectangular area; impulse sprinklers cover a round area. Impulse sprinklers do better in windy areas.
If you are fighting blight diseases in your lawn, be sure to read the Fact Sheet “Lawn Blight Diseases”. Watering recommendations vary somewhat for diseased lawns.
Click Lawn Watering Fact Sheet for a printable version of this page.
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