Many places across the country are used to dry summers, but 42 states are experiencing moderate to severe drought conditions, according to the government agency that monitors drought. And the abnormally dry weather is of course having an impact on our lawns.
We have some tips to keep your lawn thriving and as green as possible, but you’ll want to watch for any watering restrictions that your community may impose, which would limit some of your options. Not to worry: when cool-season grasses turn yellow or brown, it’s often a temporary condition.
With a lack of water and hot weather, cool-season lawns (such as Kentucky bluegrass) go into a summer dormant-like condition and in some cases turn color. The grass is not dead. These grasses can survive up to three weeks without any water. But even then, with as little as two-tenths of an inch of rain or water from your sprinkler can rehydrate the plant, keeping them going until more rainfall and cooler temperatures arrive in the fall.
[Read our Summer Series: Part 1 Extreme Heat | Part 3 Lawn Care and Disease]
When watering your cool-season lawn in a drought, do it less frequently but more thoroughly. You want the water to penetrate deep into the soil to nourish the roots of your lawn. This is a strong defense against summer stress.
This less frequently/more thoroughly approach is improving your lawn’s drought tolerance: the deeper and more extensive the root system, the better your lawn will survive dry spells with little or no rainfall or irrigation from a sprinkler or hose.
The reason you want to avoid frequent and surface-only irrigation is because what you are doing is promoting root growth near the soil surface, where they dry up and burn out more quickly in the summer heat.
Just as people struggle to stay cool, plants have a hard time in the heat and humidity. But again, resist the urge to cool the turf with light applications of irrigation throughout the day. It has no significant impact on the temperature of the canopy.
Always try to water your lawn in early morning hours, when the air temperature is usually the coolest of the day. If you water later in the day — when the sun is baking the ground and the heat and humidity are at their highest, what you are actually doing is using water to lock heat inside the soil, adding stress to the root system, not relieving it.
Keep cutting the grass in a drought, but when you mow consider raising the mower deck to a height of at least 3.5-inches. Taller blades keep the soil canopy cool, they will grow deeper roots and will survive off of more nutrients and water that are found deeper in the soil.
When rainfall returns following a drought, Kentucky bluegrass will emerge from its dormancy and get back on a normal growth schedule.
Other cool-season species such as fescues can stay green and hold up in a drought if they can access water and nutrients through the deeper and stronger root system that we talked about earlier. You’re helping the grass wait out the drought.
Recognize some of the signs of drought stress in your lawn: wilting blades of grass that fold in half, a proliferation of weeds, footprints or tire tracks that remain on the grass surface for several minutes.
When your lawn is in summer stress, pause projects such as aerating and dethatching. It is best to avoid applying fertilizer to a drought-stressed lawn. Try to wait until late summer or early fall to make that fall application.
Note: Warm-season grasses, such as Bermuda and St. Augustine and zoysia grass hold up much better in dry and hot conditions and do not require the same critical attention to deal with summer heat stress.
As we covered in Part 1 of this series, keep up your routine mowing schedule and never cut more than one-third of the grass stem at any one time.
If you avoid excessive irrigation and keep to your regular mowing schedule and cut blades at a higher-than-usual height, you’re doing your part to help your lawn in a drought. You’re also reducing the chance of seeing disease in your lawn, which we cover in Part 3 of our series.
Your local independent lawn and landscape dealer can give you advice on any specific problems or concerns that you have. They can also recommend reputable landscapers who can test the quality of your soil, provide the proper nutrients, and give you expert advice on how to keep your lawn looking great. To find a dealer near you, click here.