How Often to Water Your Lawn in Hot Weather. Grass needs between 1 inch and 1 ½ inches of water per week (either from irrigation or precipitation). If there is no rain, water your grass two to three times, each for approximately 30 minutes.
For most grasses, 1-2 weekly waterings of 25-30 minutes should provide the needed 1 inch, adjusting based on your system and soil type. Signs of underwatering include thinning, yellowing,or browning grass.
The ideal watering schedule is once or twice per week, for about 25 to 30 minutes each time. Taking care of a lawn doesn't have to be an overwhelming, all-consuming task.
For example, rotor sprinkler heads might require 20 to 30 minutes of straight watering time, while a traditional spray head zone will only need 5 to 10 minutes.
Approximate Running Time: To provide your lawn with 1 inch of water per week, run your spray sprinklers for about 2 hours weekly, ideally split into three 20-minute sessions in early mornings.
Watering in the morning also helps your lawn stay cooler throughout the hottest parts of the day, decreasing the amount of heat stress for the turf. If you are unable to water in the mornings, early evening (between 6:00 PM and 8:00 PM) is the next best time.
In the late spring, rotor irrigation zones typically need to run 30-45 minutes per zone, and spray irrigation zones typically need to run 8-12 minutes. We recommend watering 2-3 days a week during late spring. In mid to late summer with extreme heat, your lawn will need more water.
Most turfgrass plants can stay in a dormant state for at least 3-4 weeks without the grass dying (longer if the dormancy is induced by cold). If drought goes beyond the 4 week mark, apply enough water to rehydrate the grass slightly and wet the soil down to a 5-inch (12.5 cm) depth.
The average system uses approximately 15-16 gallons per minute, per station. Here is an easy formula to help you calculate the approximate amount of water you are using each month.
Lawn Watering Practices
Frequent watering encourages shallow root growth and unhealthy grass. Deep, less frequent watering encourages grass roots to grow deeper into the soil reservoir from which to draw moisture. Deep roots also mean the lawn will be less affected by surface drying.
Why is my grass yellow? Yellow grass is a sign of low nutrition and can be caused by too little water, too much water, blunt cutting blades on your mower, or lawn diseases. Water your lawn if it's too dry and aerate your soil if puddles are collecting. Sharpen your cutting blades on your mower for a cleaner cut.
What time of day should you water your lawn during extreme sun and heat? “Irrigate early in the morning whenever possible,” Goatley said. “Irrigating during the heat of the day is considered to be very inefficient as evaporation rates are typically highest during this time of day.
You must water your lawn in hot weather at least three times per week, as long as you soak the soil to a depth of at least six to eight inches. Watering frequently maintains a shallow root system that is more susceptible to high heat.
In the spring and fall, sprinklers should run a few times a week for short intervals (no more than 15 minutes per zone). During summer months, when temperatures are hot and dry, sprinklers should run longer (up to 30 minutes per zone) depending on how much sun exposure the area receives.
Your goal is for the lawn to receive enough water to keep the soil slightly moist in the upper six inches of soil. This usually requires at least one inch of water per watering session or around 30 minutes of watering, however, each lawn is different.
No amount of water will revive dead grass. So long as it's still healthy, a dormant lawn can typically survive for several weeks without rainfall or irrigation. If your lawn is dormant rather than dead, it should start to green up again once it receives the water it needs.
It is important to note that you should avoid watering your grass during the hottest part of the day, typically between 10am and 4pm. During this time, the sun is at its strongest, and the water is more likely to evaporate before it can soak into the soil.
1-2-3-2-1 watering technique:
In April water 1 day/week. In May ramp up to 2 times/week. In the heat of the summer water 3 times/week. In September drop back to 2 times/week. In the fall drop back down to 1/week.
A watering session should be long enough to soak the area sufficiently so all the roots receive a beneficial drink. Sprinklers should be set to run for about 30 to 35 minutes at a time twice a week. Your goal is at least 1″ of water a week for your lawn.
If you're not sure how much time it takes for your sprinklers to spray an inch of water, you're not alone. A fixed spray head nozzle might take ~30 minutes to apply 1 inch of water, whereas a rotary nozzle could take 3x as long to apply the same amount.
If your grass's roots are too short in summer, they are more likely to dry out in the hot summer sun, even if you water daily. Even in the driest conditions, excessive watering can result in soil flooding and a lack of oxygen for your soil and roots. When this happens, your grass is a prime target for drought stress.
The rule of thumb for watering an established lawn is, “water as deeply and as infrequently as possible.” Deep and infrequent irrigation stimulates root growth, resulting in healthy, drought tolerant, and pest resistant turf.
Most properties do not require regular automatic watering until around Memorial Day. If the temperature reaches above 70 degrees consistently for more than 3 days then begin automatic watering or run one cycle manually. Temperatures in the 60's or below you may water once or twice a week or water manually.