Lawn watering seems like a simple task, but there is a surprising amount of technique — along with lawn watering faux pas — that goes into this routine lawn maintenance. Proper timing and a few lawn watering tips will make your grass healthier while conserving water and preventing runoff. Professional lawn watering tips make a lot of sense when you understand the logic behind them, and knowing a few can save you some green while keeping your lawn robust and healthy.
The Best Grass by Climate
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Lush, water-saving lawns start with the correct grass for the climate. Cool-season grasses like Kentucky bluegrass or fescue grow in northern parts of the United States where there tends to be more water and fewer dry spells. Warm-season grasses like Bermudagrass and zoysia are adapted to combat southern temperatures and less rain. If you plant cool Kentucky bluegrass in the South, it will likely need 50 percent more irrigation than a grass variety that is better suited to the region.
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No matter what type of grass you choose, look for one that is certified by the Turfgrass Water Conservation Alliance (TWCA). (Yes, that's a thing.) The TWCA facilitates and encourages the development of drought-tolerant grass strains. Grasses bearing its mark use up to 30 percent less water than other grass varieties and better survive drought. Many TWCA grass varieties will also stay green up to three weeks during drought conditions.
Water Deeply Less Often
When it comes to lawn watering, less is more. When you water your lawn, you want to wet the top 6 inches of soil and allow the lawn to dry out a bit between waterings. Doing so encourages grass roots to stretch into the soil, creating a solid base for the lawn.
If you water your lawn every day or so, you're actually doing it a disservice. Lawns that receive frequent watering don't need to develop deep root systems since water is always available at the earth's surface. The result is shallow grass roots that grow out rather than down, creating a lawn that doesn't tolerate drought, foot traffic, or disease.
It's better to water your lawn deeply once or twice a week (or up to three times a week depending on the climate) than to water it every day or every other day.
Lawn Watering Amounts
Although lawns may need a bit more water during a drought, most yards require 1 to 1 1/4 inches of water per week. You can use a simple rain gauge to measure how much water your lawn has gotten and how much more it needs. If you don't have a rain gauge, you can always sit an empty tuna can on your lawn. Measure the amount of water in the can to determine when you're done watering.
You can also test your watering with a screwdriver. When you're done watering the lawn, poke a long screwdriver into your yard. The screwdriver should easily slide at least 6 inches into the soil. If you meet a lot of resistance when inserting the screwdriver, your lawn likely needs more water.
Lawn Watering Tips for Sprinklers
An in-ground irrigation system with pop-up sprinkler heads is hands down the easiest way to water your grass. These systems typically include a timer to automate lawn watering tasks. If you lack such a system, you can use a portable lawn sprinkler to irrigate. If so, use a pulsating sprinkler. Pulsating sprinklers spray water and then pause for a few seconds, allowing the moisture to soak into the earth before watering it again. This saves water and allows the grass to get more of it before it evaporates.
The exception to this rule is when you water grass seed and seedlings. The pressure from a pulsating sprinkler can prove to be too much, washing away seeds and uprooting seedlings. Use an oscillating sprinkler on new lawns until they establish themselves.
No matter what type of sprinkler you use, make sure you monitor the water flow rate. If you see water running down your street when irrigating, you're using too much water or applying it too quickly. Adjust your sprinkler as needed to prevent runoff and wasted water.
When to Water Lawns
Water that evaporates before your lawn can soak it up doesn't do your grass any good. This makes the absolute best time to water between 4 a.m. and 10 a.m. in the Eastern United States. If you can't water in the morning, aim for late in the afternoon. Never water your lawn in the evening, however.
Without any sunlight to dry it out, the soil in your lawn can hold too much water. This promotes root rot, fungal diseases, and an increase in insect pest populations. If the day gets away from you, wait and perform your lawn watering the next morning rather than watering at dusk.
The rules are different in the Western U.S., however. If you live out West, watering between 10 p.m. and 6 a.m. is best. This is when the winds are calm and the humidity is high, ensuring the water won't evaporate too quickly.
Wherever you live, the key is to water when winds are calm and avoid watering during the hottest part of the day.
Managing Lawns During Drought
It's important to conserve water in a drought. It's so important, in fact, that your local or state government may limit the amount of irrigation you're allowed to perform. If you know a drought is imminent, gradually reduce the amount of water your lawn receives to cushion the shock. Going from regular lawn watering to nothing is hard on grass, so taper your water usage if you can.
Many high-end irrigation systems use sensors to monitor the weather and soil conditions. Because they turn on the sprinkler only when you need it, these sensors can save you a lot of water. If you need to save water, consider turning on only the sprinklers that cover exposed areas of your lawn. Doing so will allow you to water only where you absolutely need to and skip over shaded areas that fare better in droughts than sunny spots.
Skip the fertilizer during dry spells as well. Fertilizers can burn or damage stressed grass and are best avoided in extreme conditions. Fertilizers may also encourage thirsty new growth that needs more water than usual.
Winter Lawn Watering
Your grass is likely to go dormant over the winter, but that doesn't mean you can stop watering altogether. There's no point in watering frozen ground, so don't bother with winter watering if you live in a Northern climate with cold winters.
If you live in a warmer region, however, your lawn would likely benefit from a deep watering twice a month during the winter season. Water only when the temperature reaches or exceeds 40 degrees Fahrenheit and when rainfall isn't sufficient.
Winter watering also works best in the morning or early afternoon. If the temperature drops overnight, wet plants are far more likely to freeze or suffer frost damage. Watering early gives the lawn a chance to dry before it freezes overnight.
Don't make the mistake of counting on snowfall to water the lawn for you. As a rule of thumb (with some variations), it takes about 10 inches of melted snow to make 1 inch of water. Snow may not provide enough water.