Q: How much water does grass need?
A: The watering schedule depends on the type of soil, sandy or clay, and whether the property is flat or on a slope. If too much water is applied, nutrients will leach through the soil faster taking them too far down for grass roots to reach them. With too much water, grass won’t be as green, may lead to disease, and it will encourage weeds to thrive in that area. Not enough water will cause grass to go dormant and turn brown, eventually leading to death. Depending on the age and type of grass, sometimes grass can survive a drought. In order for grass to survive a drought, nutrient and pH levels need to be optimum and grass needs a couple of years or more under its belt for the roots to get fully established. So if you have fairly young lawn, make sure grass is taken care of during the summer months until roots are well established.
If an in-ground sprinkler system is being used regularly, DO NOT assume it’s watering your lawn perfectly! Sprinkler heads have to be properly adjusted every year. If browning occurs on an irrigated lawn, check to see how the heads are spraying. A sprinkler system is only as good as it sprays! It can be such a fine adjustment, not even noticeable unless studied, that can make a world of difference. This is may only be a problem during hot, dry months. Soil with optimum levels for soil pH and nutrients, a well balanced lawn care program, and an irrigated lawn should not have browning! In just about every heat stressed lawn you can find disease and more often than not, turf disease is brought on as a result of the heat stress. Once grass is hit with one stress, it is very susceptible to other stresses (disease). Please compare these two photos.
Photo A, no bueno! Notice the difference between A and B, the vertical spray. In photo B, from the start of the sprinkler head to where the water ends, grass is getting wet and it is noticeable. If you cannot see the mist between the top of the spray and the grass, it is not enough water! That mist should be easily visible. The condition of the sprinkler head, water pressure and the proximity of the sprinkler heads all play a role into creating an effective irrigation system. Photo A will also cause issues when seeding in the fall time!
WATERING SCHEDULE (irrigation that is properly installed/adjusted with good water pressure)
*Sprinkler heads that rotate a full 360, require twice the amount of time.
SANDY SOIL: Water leaches through the sand much faster than other soils. This requires less water than other soils to get the soil moist four inches down where the roots extend. Unfortunately, sandy soil dries quicker than other soils. Instead of increasing the time the lawn is watered, just water more frequent. When temperatures are in the 90’s and above, you may need to be watering twice a day, 15-20 minutes each zone. In cooler weather, water once a day for the same amount of time.
CLAY SOIL: You have to use heavy watering to get where the roots extend. When temperatures are above 90 degrees, you may need to water once a day, 30-40 minutes each zone. Below 90 degrees, water once every other day, for the same amount of time.
SLOPE: See sandy soil. This will prevent water runoff.
Every lawn should be watered as early as possible, 4-7 am is ideal. If you have to water twice in one day, water a 2nd time 12 hours later. Watering in the afternoon, when the sun is at its strongest, could have the reverse effects. Wet grass could act as a prism for the beaming sunlight and make it easier for the sun to burn up your lawn.