The average American family uses more than 30 percent of its water on irrigation. Across the United States, that means 7 billion gallons of water are used per day to water our lawns and gardens. Unfortunately, poor irrigation practices mean that more than 50 percent of that water is lost to runoff and evaporation.
Here in the Lowcountry, although water is seemingly abundant, smart irrigation is an important conservation practice that reduces the impact irrigation-related runoff has on waterways. Additionally, good irrigation helps lawns thrive and protects against plant disease. In the quest to have the best-looking yard on the block, the following irrigation tips will keep your lawn healthy and protect the water resources we love.
Have your soil tested
Visit your local Clemson Extension office and have your soil tested. A soil test will provide recommendations for lime or fertilizer that may be needed to create a thriving lawn that can withstand our tough summers. And, if you are only applying what your lawn needs, you will be reducing the amount of excess fertilizers picked up with runoff and carried downstream.
Adjust mower height
Using the right mower height for your grass promotes a denser root system, helping to out-compete weeds and making your lawn drought tolerant. Mowing height varies between grass species, ranging from 1 to 4 inches, so you’ll need to adjust your mower accordingly, making sure to only remove 1/3 of the grass height each time you mow. The Clemson Home and Garden Information Center factsheet, “Mowing Lawns,” offers specific information for your grass type: https://hgic.clemson.edu/factsheet/mowing-lawns/.
Know when to water
Overwatering lawns makes grass more susceptible to disease, encourages weed growth, and results in runoff into nearby storm drains. And, let’s not forget the impact of high water bills on our wallets. Use a rain gauge to monitor rainfall or take an evening stroll across the lawn and check to see if you leave “footprints,” a sign that lawns may need supplemental irrigation.
Water deeply, not often
Unless you are establishing a new lawn, don’t water daily. Water deeply but infrequently to promote a deep root zone that can better access soil moisture. In summer months, lawns need approximately 1inch of rainfall per week or you will need to irrigate. To irrigate, apply 0.5 inch of water twice a week for lawns in sandy soils; apply 1 inch of water once a week for lawns in clay-ey soils. If you can easily press the tip of a screwdriver several inches into the soil, you’ll know it is well-watered. Set your alarm early and plan to turn on your sprinkler before 10 a.m. in the morning to reduce the amount of water lost to evaporation.
As water comes in contact with minerals in the soil, organic matter, and microbes, the amount of salt and nutrients present will vary. Too many or too few of any of these in your irrigation water can prove harmful to the lawn. If your irrigation system is tied into a pond or a well, have an irrigation water test performed. Bring a pint-size sample of your water to your local Extension office and ask for the “Special Test.” This test provides information on any water quality concerns and your Extension agents can provide next steps to help protect your lawn investment.
Calibrate your sprinkler
Calibrate your sprinklers to ensure you aren’t over, or under, watering your lawn. Place empty food cans at random locations around your sprinkler heads in your yard. Calculate the average water collected (in inches) after running your sprinkler for 15 minutes. Multiply that number by four to find out how many inches of water are being applied per hour via your irrigation system.
If establishing a new landscape, consider more drought-tolerant options.
Zoysiagrass and bermudagrass are the most drought-tolerant turf grasses for our coastal communities. Alternatively, abandon turf grass all together and create a flowering meadow, perennial shade garden, or backyard greenscape with native plants that are well-adapted to our soils and climate. Once established, these landscapes have lower irrigation and fertility needs.
Visit the Home and Garden Information Center at https://hgic.clemson.edu or call your local county Extension office for more information on these and other practices.
Guinn Wallover is a Natural Resources Extension agent for the Clemson Extension Service.
Rain barrels now available
Rain barrels are a smart irrigation practice: Collect rainwater flowing off of your roof in rain barrels. The Ashley Cooper Stormwater Education Consortium’s annual rain barrel event is going on now. Learn more and purchase a 50-gallon rain barrel for a reduced price at https://www.rainwatersolutions.com/products/acsec-ivy