Lawn Drought

Kenosha News – July 21, 2016

Barb Larson, Horticulture Educator

Question: A nice lawn is important to me. I don’t mind letting it turn brown but the grass is almost crispy and I don’t want it to die. Is there anything I should do to keep the lawn alive if it doesn’t rain? J.S.

Answer: Kentucky bluegrass, which is the predominant lawn grass in Wisconsin, can survive sixty or more days without water. The plants cope with drought by allowing the leaf blades to die while keeping the crown of the plant alive. Beyond two months the crown may die. Some of our lawns contain perennial rye grasses and/or fine fescues in addition to Kentucky bluegrass. Perennial rye grasses can’t survive drought and are dead when brown colored. During the 2012 drought we discovered fine fescues were not as drought tolerant as hoped.

You can extend the length of time your lawn will survive by not applying any fertilizers, weed killers, insecticides or fungicides when it is brown and dormant.

Lawn survival is affected by soil conditions and usage. Lawns grown on hard compacted soil need more help than a lawn on high quality soil. Lawns on a sandy or clayey soil are not as drought tolerant as those on loamy or silty soil. Grass that is walked or played on extensively, such as athletic fields, will die sooner than grass with little to no foot traffic. I irrigate my lawn just enough to keep the crowns alive because the soil is sandy loam and I have two greyhounds that have made pathways in the lawn.

Green grass needs one inch of water per week to stay green and growing. But a dormant lawn requires much less water to keep the crowns alive. You can apply one quarter of an inch of water per week or about one half of an inch every two weeks to keep the crowns hydrated. This small amount of water should assure your lawn will green up after rain returns. It takes at least two weeks after the soil is hydrated for the grass to turn green again. Because Kentucky bluegrass spreads by rhizomes, it will fill in small open spots left from dead ryegrass and fine fescue.

Don’t apply more than recommended amount of water or your lawn could start growing instead of remaining dormant. Once the lawn is green you need to keep it that way. Going back and forth between green and brown is very stressful on grass plants.

Barb Larson is horticulture educator for Kenosha County UW-Extension. Questions can be emailed to barbara.larson@kenoshacounty.org or call 262-857-1942