Water is essential to the health of your lawn, in more ways than the obvious. Turf grass also uses water as an internal cooling mechanism in the really hot days of summer, and shade grass especially needs water as an external cooling agent.
More often than not, we see lawns that are watered too frequently but not long enough each time. Frequent, shallow watering encourages shallow roots and contributes to thatch accumulation, soil compaction, and even weed seed germination. Shallow roots also make your turf less healthy and more prone to disease, insect infestations, or damage from heat and cold. Deep watering produces deep roots and healthier grass.
Everyone's lawn is different when it comes to soil type, slope, and the condition of the lawn. Moreover, water pressure, a big factor in watering your lawn, differs from house to house. But we can give you easy step-by-step instructions to find your own watering schedule that will best benefit your lawn. It usually takes less than an hour of your time, and then you'll know how much and when to water for the rest of the summer.
Your lawn needs 1" to 2" of water per week, and each time you water, the water should reach a depth of 6" down into your lawn.
The next time you're getting ready to water, set an empty tuna fish-sized can in each area where you're going to put your sprinkler. (If you have an automatic sprinkler system, set the tuna cans in strategic areas throughout your lawn before the sprinklers come on.)
Turn on your sprinkler for 30 minutes.
Turn off your sprinkler.
Stick a ruler into the tuna can and see how much water is in it.
If you don't have 1/2" of water, keep watering (time yourself) until you do.
Now let's determine if your lawn needs 1" of water per week or 2" per week.
After you have gathered ½" of water in your tuna can, take a 6" screwdriver and push it into your lawn, up to the hilt. If it goes in easily, you're done! If not, you need to water some more, perhaps gathering up to 1" in your tuna can. (Caution: If, at any time, water is running off and down the street, you need to stop for 20-30 minutes, let the water soak into the lawn, and then resume watering. This usually occurs due to heavy clay soil or because your soil is compacted.
If you have automatic sprinklers be sure you check them from time to time to make sure you're getting complete coverage and that a sprinkler head isn't misdirected and possibly flooding an area by pointing downward.
Water early in the morning, if possible, to avoid evaporation during the heat of the day, or the development of fungus and diseases from being wet at night. However, watering at any time is immeasurably better than not watering at all!
Ideally, your lawn needs to be watered when it needs water. A set schedule may be easiest for most of us, but sometimes just doesn’t fit the needs of the grass. Likewise, while we can recommend what works for most lawns, it may not work for all.
Signs that your grass needs water are wilting, a bluish-grey appearance, or “footprints” left when you walk through your lawn. Grass wilts when the loss of water from the plant (evaporation through the leaf, called transpiration) exceeds that taken up from the root system. (Kind of like us–when we’re out in the heat and sweat a lot, we need water or we’ll definitely wilt!)
The type of soil in your lawn affects your lawn’s watering needs. Coarse, sandy soil absorbs water faster, but retains less water than fine soil like loam and clay. It will take less water to reach a 6” depth in sandy soil, but you will need to water more often. On the other hand, a heavy clay soil will absorb water slowly, and you want to be careful that you don’t have water running down the street. You may have to water twice in one day to reach the 6” depth.
Water pressure is an important factor, which is why we recommend using tuna cans above to actually measure how long it takes to accumulate an inch of water. Water pressure can vary from house to house.
Cultural practices on your lawn, like mowing and fertilization, will also affect watering needs. A lush, vigorously-growing lawn will actually use more water than a poorly performing lawn.
Windy weather will dry out your soil and your lawn. In periods of high wind, you may need to increase your watering.
If your lawn is sloped, you will need to water the top of the hill much more than the bottom.
If you have fescue, rye or other cool-season grass, you may follow the same guidelines outlined here, but you may also have to water lightly every day if temperatures are in the nineties or above. “Shade” grass is not really sun intolerant—it is heat intolerant. A fescue lawn in full sun will do fine in moderate temperatures. During the hot summer, when temperatures soar, a daily light watering early to mid-afternoon will help cool off the grass. You will still need to do your deep watering twice per week or more frequently if you notice it wilting between waterings.
If you have newly-seeded grass, you will need to keep it moist throughout the germination period. Water it lightly just to a depth of about 1”. Do not overwater or your seed will wash away or clump up in puddles. If the seeded area is bare, you may want to lightly cover it with grass clippings until it germinates. If it dries out, it will die.
If you have newly-sodded grass, water lightly twice per day until it is rooted down.
Be sure your lawn has good drainage. If you frequently have standing water, you may need to aerate your lawn or in severe cases, consider digging swales or putting in a French drain system, or bringing in topsoil to raise the lawn higher.
What if you can’t water? During the summer, your water bill may get too large, or we may have periods of water-rationing during drought, or maybe you just can’t get out and water. Bermuda lawns may begin to go dormant. This is the grass’ protective strategy. It will prematurely turn brown and go into drought-induced dormancy. It’s not dead, it’s just resting in sleep-mode. When the fall rains come, it should green back up again. This isn’t the healthiest thing for the grass, but it will usually survive just fine. Fertilization, even when it’s brown (the root system is still active,) will help it to be healthier when the fall rains come. If you have a fescue or bluegrass lawn, it MUST have water, or you will lose most of it.
If you have to cut back on watering, leave your lawn a little higher than normal, rather than mowing it short, to help it cope with the heat stress