Watering 101 A typical in-ground sprinkler system provides ½” of watering, per zone, in a half an hour. This would mean that you need to run each zone of your sprinkler system for 30 minutes, 3 times a week to sufficiently hydrate your lawn.
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.
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.
Always Deep Water Your Lawn
This means water from 20 – 45 minutes multiple times a week – more on this later. If you water for only 5 – 10 minutes, you can actually harm your lawn.
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. But this still depends on numerous variables such as local water pressure, age of the sprinkler system, condition of the system, etc.
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.
Nothing should be in that area between the bottom of the sprinkler heads and the imaginary horizontal plane parallel to the ceiling that is 18 inches below. This is done to allow an even and unobstructed spray pattern from the sprinklers when triggered to extinguish the fire.
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.
Your sprinklers apply one inch in 20 minutes. This means you need to water 40 minutes per week. Divide the 40 by 7 and round up. This means that you should run your sprinklers about 6 minutes per day.
Typically, a zone can accommodate between five to ten sprinkler heads, with the understanding that each sprinkler head has a watering radius of about 15 feet. However, keep in mind that this is a general guideline, and the specific requirements of your lawn may vary.
Turf studies show that most lawns only require irrigation once every 4 to 8 days to stay healthy and green. Shallow rooted plants result from irrigating every day. Irrigating less often and applying more water per irrigation results in deeper rooted plants and a healthier turf.
Most homeowners should fertilize their cool-season turf in March, then May, then from September to October. However, UC IPM recommends that lawns in the Sierra area should be fertilized from May to June and August to September.
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.
Watering 101
Your lawn needs 1 to 1 ½ inches of water per week. A typical in-ground sprinkler system provides ½” of watering, per zone, in a half an hour. This would mean that you need to run each zone of your sprinkler system for 30 minutes, 3 times a week to sufficiently hydrate your lawn.
Running multiple zones at once is usually not possible due water-pressure and flow limitations at residential properties.
Water for the appropriate amount of time.
Depending on the size of your garden, the climate, and the time of year, you'll need to do some research into the best watering method for your lawn. We would suggest watering your garden with an oscillating sprinkler for about 20-30 minutes.
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.
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.
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.
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.
6. Lawn Sprinkler and Irrigation Systems. If you have a lawn sprinkler and irrigation system, you should know that it's naturally going to work harder during the warm summer months. If your irrigation system isn't programmed correctly or it develops a leak, you might find your water bill creeping higher than usual.
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.
A common rule that is followed for obstructions within 18 inches of the sprinkler deflector is the “three times rule”. This requires sprinklers to be positioned away from obstructions a minimum or three times the maximum dimension of the obstruction.
A typical sprinkler system with pop-up rotary heads uses approximately 15 to 16 gallons of water per minute per station. An Irrigreen smart sprinkler system uses approximately 6 gallons per minute per head when spraying about 30 feet.
Dig for Your Sprinkler System
The trenches will be relatively shallow, usually 6 to 12 inches deep, depending on your area's freeze cycles and frost severity. The trench must also be deep enough to allow the sprinklers to retract underground to prevent breakage from lawn machines.