How often should I water new sod?

Water new sod enough to keep the soil underneath it moist every day until it roots, then cut back to deep, less frequent watering. In practice that means a thorough soak on the day it is laid, daily watering in hot weather for roughly the first week, and a gradual move over the next few weeks to watering every few days, deeply, in the early morning.

The goal is not to keep the grass blades wet. It is to keep the soil just under the sod moist while new roots grow down into it.

Day one: soak it

Give the sod a thorough watering immediately after installation and keep it moist until significant root development has occurred.^[1] If you are sodding a large area, start watering as soon as one section is down,^[1] rather than waiting until the whole lawn is laid. Water until the soil under the sod is wet, then lift a corner to check that it actually is.

The first week or two: keep it moist

In hot weather, above 80°F, water the sod daily, wetting the soil thoroughly until it is well rooted.^[1] In cooler weather it dries more slowly and needs less. Do not skip days early on: inadequate irrigation can cause root dieback or dry the sod out.^[5] Newly sodded lawns need more frequent watering for the first three to four weeks than established lawns do.^[2]

Cool weather slows drying, so you can ease off on cloudy, cool days, but let the soil under the sod decide: lift a corner and adjust to what you find. If it is dry, water.

Measure the water rather than guessing. Put a rain gauge or a few straight-sided cans on the lawn, run the sprinkler, and note how long it takes to collect the depth you want. Check corners and the strips along walks and driveways, which sprinklers often miss and which dry fastest.

Best time of day

Water is best applied early in the morning, a few hours before or just after sunrise, when evaporation and wind are lowest.^[2] Night watering should be avoided unless it is the only time possible, because it greatly increases the chance of fungal disease.^[2] Virginia Tech's disease specialists add that watering around sunrise also rinses dew off the leaves and shortens the time they stay wet.^[4]

After a week: check the roots

To see whether the sod has rooted, gently tug on a corner about seven days after installation.^[1] There should be some resistance by then,^[1] and you may see new roots reaching into the soil. If it still lifts freely, keep up the frequent watering and check again in a few days.

Once it resists, start stretching the time between waterings while watering more deeply. Virginia Tech notes that sod can take larger amounts of water less often than seed, because it brings its own soil and root mass that hold moisture.^[3] Watering deeply and less often encourages roots to follow the water down.

Once it is established

For an established sod lawn, make sure the soil is moist to a depth of 3 to 4 inches each time you water.^[1] As a rule of thumb, most turfgrasses need about 1 inch of water a week, from rain or irrigation, to keep growing in warm weather,^[2] but applying a full inch at once is likely impossible on most Virginia soils, which take water in slowly,^[2] so smaller amounts every three to four days may be needed to avoid runoff.^[2] Let a rain gauge and the look of the grass guide you.

Keep watching it through the first summer. Seedling or recently established lawns, less than a year old, have little to no drought tolerance.^[2]

Too much water is a problem too

Soggy sod is not better sod. Overwatered lawns frequently develop excess leaf growth and summer fungal diseases,^[2] and lawns should not be watered so much that water stands for long periods in low or poorly drained areas.^[4] If the soil under the sod squelches or water pools, skip a day.

Fall and winter sod

Sod laid late in the year still needs water. Dormant sod still needs moisture, and a straw-colored warm-season sod may need watering even in the dead of winter^[1] if the season is dry. Water when the soil under the sod is dry and the ground is not frozen.

Stop and call a pro if

• The sod keeps browning even though you water on schedule and the soil under it stays moist. That points to a cause other than water; see why new sod turns brown.
• Water pools or runs off before the soil underneath is wet, which points to compacted soil or a grading problem.
• Your irrigation system leaves dry strips you cannot fix by adjusting the heads, or it leaks. Virginia's contractor regulations treat installing and repairing lawn sprinkler systems as a licensed specialty, landscape irrigation contracting.^[6]

For the full installation, see how to lay sod, and for watering other new plantings, how often to water new plants. Browse the lawn and landscaping answers, see sod installation services, or find lawn and landscaping businesses near Blacksburg. If you would rather hand it off, describe your sod job and local businesses can quote it.