Effective summer watering focuses on applying moisture deeply and efficiently to encourage strong root growth that can withstand heat stress. Watering should penetrate the soil deeply rather than just wetting the surface layer. This strategy prevents the shallow root systems that are susceptible to drying out during periods of intense sun and heat.
Measuring Water Application for Deep Roots
The most accurate way to determine your watering duration is to measure your sprinkler system’s output directly. Lawns generally require a total of 1 to 1.5 inches of water per week during the summer months to remain green, though this amount may increase to 2 inches during intense heat waves or drought conditions. To promote drought tolerance, this total weekly amount should be delivered in two or three separate sessions, not daily. This means each watering session should aim to deliver approximately 1/3 to 1/2 inch of water at a time.
You can calculate the duration by performing a simple irrigation audit using catch-cans, such as tuna cans or similar straight-sided containers. Place several of these containers randomly across the area covered by your sprinkler, making sure they are not obstructed by the spray. Run your sprinkler for a set time, such as 15 or 30 minutes, and then measure the depth of the water collected in each can using a ruler. Average the measurements from the cans to find your system’s precipitation rate in inches per minute or hour.
For example, if your cans collected an average of 1/4 inch of water after 15 minutes, you would need to run the sprinkler for 30 minutes to deliver the target 1/2 inch of water. This duration becomes your established watering time for that zone. The goal of this deeper watering is to moisten the soil down to a depth of six to eight inches, which coaxes the grass roots to grow downward.
Establishing the Best Time and Watering Schedule
Once you have calculated the necessary duration for a deep watering, the next consideration is the optimal time and frequency for the sessions. The best time to water your lawn is in the early morning, typically between 4 a.m. and 10 a.m. This window allows the water to soak into the soil before the sun’s heat causes excessive evaporation, maximizing the efficiency of your water application. Watering during the day’s heat can result in up to 50% of the water being lost to the air.
Watering early in the morning allows the grass blades to dry completely as the day warms up, which prevents fungal diseases. When grass remains wet for long periods, such as from watering in the late evening or overnight, it creates an environment conducive to the spread of turf diseases. The strategy of watering deeply and infrequently, two to three times per week, forces the turf to develop a robust, deep root system.
How Soil and Grass Types Change Watering Needs
The duration calculated using the catch-can method may need slight adjustments based on your soil and grass type. Soil composition significantly influences how quickly water is absorbed and how long it is retained.
Sandy soil, for example, allows water to drain very quickly. While your deep watering duration is still correct, you may need to apply it slightly more often to compensate for the rapid drainage.
On the other hand, clay soil absorbs water slowly and holds it for extended periods. If you apply water too quickly to clay-heavy soil, the water will simply run off before it can penetrate the root zone. In this case, you should use a “cycle and soak” method, breaking your total watering duration into two or three shorter segments, separated by a 30 to 60-minute pause. This allows the water to soak into the slow-draining soil without causing runoff.
Grass species also exhibit different tolerances to heat and drought. Cool-season grasses, like Kentucky Bluegrass or Fescue, actively grow in cooler weather and often struggle more during the intense heat of summer, sometimes requiring the higher end of the weekly water requirement to prevent dormancy. Warm-season grasses, such as Bermuda or Zoysia, are adapted to heat and typically maintain better color with less water, though they still require deep watering to sustain their health. Adjusting your calculated watering time based on the soil’s absorption rate and the grass’s response to summer temperatures ensures the moisture is delivered effectively.