The duration for watering each section of grass is not a fixed number but is determined by achieving deep soil saturation without runoff. Efficient watering focuses on delivering a precise amount of water to the root zone, rather than setting a fixed timer. Inefficient practices waste resources, encourage weak root systems, and leave the turf susceptible to environmental stress. The duration needed depends entirely on your sprinkler system’s output rate and your lawn’s specific needs.
The Principle of Deep and Infrequent Watering
The foundational reason for managing watering duration is to encourage a strong, drought-resistant root system. Shallow, frequent watering keeps only the upper soil moist, causing roots to remain near the surface where they are vulnerable to heat and drying. This results in weak turf that requires constant water.
Deep watering forces the roots to grow downward in pursuit of moisture, making the plant more resilient. The goal is to moisten the soil profile to a depth of approximately four to six inches during each session. Allowing the upper soil to dry slightly between watering events ensures oxygen reaches the roots and incentivizes the development of a deeper network.
Variables That Dictate Watering Duration
The time required for soil saturation depends on two primary factors: soil composition and the type of grass. Different soil textures absorb and retain water at vastly different rates.
Clay soil absorbs water slowly but holds moisture for a long time, often requiring shorter, repeated cycles to prevent runoff. Sandy soil absorbs water quickly but drains rapidly, meaning it needs a longer run time to soak the root zone completely.
The type of turfgrass also influences water requirements. Cool-season grasses, such as Kentucky bluegrass, generally need about one to one and a half inches of water weekly to thrive. Warm-season varieties, such as Bermuda grass, may require slightly less.
Calculating Your Specific Watering Time
Determining the exact minutes needed requires a practical measurement known as the “catch can” test, as sprinkler systems and lawn zones vary widely in their water delivery rate. This calibration method gives you the precipitation rate specific to your equipment and water pressure.
To perform the test, place five to nine straight-sided containers, such as tuna cans, randomly across a single watering zone. Run the sprinkler for a fixed time, typically 15 minutes, and measure the depth of water collected in each can with a ruler. Calculate the average depth collected across all cans to determine your sprinkler’s hourly precipitation rate.
For example, if your average collection is one-quarter inch in 15 minutes, your system delivers one inch per hour (0.25 inches multiplied by four). To achieve the recommended one inch of water for a deep soak, calculate the total minutes required based on your measured rate. If your system delivers one inch per hour, your duration is 60 minutes for that zone. This process must be repeated for every distinct watering zone, as variations in sprinkler heads, water pressure, and coverage will result in different run times.
Optimal Watering Frequency and Time of Day
Once the correct duration is calculated, the focus shifts to frequency and timing. Watering should be done infrequently, typically two to three times per week, rather than daily, to maintain the deep-watering principle. This schedule allows the soil to partially dry out between sessions, which is beneficial for root health and oxygen exchange.
The best time of day for watering is early morning, ideally between 6 a.m. and 10 a.m. Watering during this cooler period minimizes water loss from evaporation. An early morning schedule also allows the grass blades to dry completely by midday, which significantly reduces the risk of fungal diseases that thrive in prolonged damp conditions overnight.