Begin watering new turf grass sod within a half hour after it’s laid on the soil. Apply at least 1″ of water so that the soil beneath the turf is very wet. Ideally, the soil 3 – 4″ below the turf is very wet. Water 2 times daily, once in the early morning and once in the evening. Water each time for 25 minutes. Extreme heat (85F+) or wind requires watering 3x a day. Rain greater than 1″, substitutes for one day of watering. You cannot water new sod too much, unless it results in standing water. Standing water should be allowed to drain off.
Make absolutely certain that water is getting to all areas of your new lawn, regardless of the type of sprinkling system you use. Corners and edges are easily missed by many sprinklers and are particularly vulnerable to drying out faster than the center portion of your lawn. Also, areas near buildings dry-out faster because of reflected heat and may require more water.
Water as early in the morning as possible to take advantage of the daily start of the grass’s normal growing cycle, usually lower wind speeds and considerably less loss of water because of high temperatures evaporation.
If the temperature approaches 100F or high winds are constant for more than half of the day, reduce the temperature of the turf surface by lightly sprinkling (syringe) the area. This sprinkling does not replace the need for longer, deeper watering, which will become even more critical to continue during adverse weather conditions.
During the rest of the growing season, most lawns will grow very well with a maximum total of 1″ of water a week, coming either from rain or applied water. This amount of water, properly applied, is all that is required for the health of the grass, providing it is applied evenly and saturates the underlying soil to a depth of 10 – 15 cm (4-6″).