Let your Grass go Dormant
Many of today’s regionally adapted grasses can handle a period of drought or heat and if they are given proper care they can actually thrive when better conditions prevail.
Grass has the ability to go dormant during adverse conditions. Dormancy is simply a state of reduced water usage where the grass plant focuses its resources on the roots.
Summer dormancy is a normal response to the stress of heat and drought. Dormant grass will turn brown and is often considered unsightly, but it will recover when conditions improve. Most grass plants can stay in a dormant state for at least 3 to 4 weeks without the grass dying. The length of dormancy depends on the genetics of the species and the overall health of the plant.
You can aid your lawn’s recovery by following these tips.
If drought goes beyond 4 weeks, apply enough water to re-hydrate the grass slightly and wet the soil down to a 5-inch (12.5 cm) depth. This will not green up the grass in most cases, but it will keep the plant alive.
Mow the grass at the top end of recommended height. To minimize stress, mow only as needed, early in the morning or late in the evening. Use a sharp blade and remove no more than one-third of the grass leaf blade.
During dormancy caused by heat or drought, avoid excessive fertilization. The dormant grass will not actively process large quantities of nutrients. Excessive nitrogen applications before or during a drought can promote top growth at the expense of rooting activity and cause injury to the grass plant.
Some weeds thrive during reduced water situations because they have large tap roots that hold water. Because a wide application of herbicide can further stress the dormant grass, spot treat weeds with an herbicide or remove the weeds by hand.
Because the grass is dormant it is not able to readily repair itself, reduce traffic on the lawn as much as possible. Avoid any activity on the grass during the hottest times of the day.
When cooler, wetter weather returns, water deeply to restore soil moisture. This will wash dust off the grass blades, rehydrate the plant, and jump-start root growth.
You Can Design to Weather a Drought Too:
The first step in the drought-proofing process is to consider modifying your basic landscape design. Start by reducing large mounds or steep slopes that encourage water to run off before it can soak into the soil.
Increase natural air movement by selective pruning and/or improving the spacing of shrubs and trees that block the prevailing winds. While shade will reduce a lawn's need for water, it can also cause the grass to be too succulent and delicate to survive a severe drought.
Next, improve the soil under your lawn to the greatest extent possible. This requires a soil test to determine what amendments may be required. Soil amendments may include lime or sulfur to correct the soil's acidity, organic material, or the addition of good topsoil.
While it's always best to improve the soil before your lawn is planted, the soil of existing lawns can be improved by annual or biennial (every other year) core aeration and topdressing with required amendments.
If you are getting ready to put in a lawn, select new and more drought-tolerant species and varieties of grass which are especially suited to your area. The Turfgrass Extension Department at Purdue University published a partial list of select grasses (commonly grown in Indiana) rating their (1) drought tolerance and (2) relative irrigation requirement to look their best:
Zoysiagrass – (1) Excellent (2) Low
Bermudagrass – (1) Excellent (2) Low
Turf-type tall fescue - (1) Very good (2) Low to Medium
Kentucky bluegrass - (1) Good to Very good (2) Medium to High
Fineleaf fescue – (1) Good (2) Low
Perennial ryegrass - (1) Poor to Good (2) High
Annual bluegrass – (1) Poor (2) Very high
Roughstalk bluegrass – (1) Poor (2) Very high
Annual ryegrass – (1) Poor (2) Very high
Consider using sod that is grown in your area for its drought tolerance because it will create a mature lawn almost instantly.
If you are improving an existing lawn, consider using new, more drought-tolerant varieties of grass that are the same species as what you now have.
A top-quality garden center, a local university turfgrass extension specialist, or a sod producer in your area can help you determine which variety of grass is best for your climate.