Deep and infrequent watering maintains a healthy root system and reduces weed infestation, as opposed to light and frequent irrigation.
Water is essential for turf seed germination, leaf formation, cooling, food manufacture, and nutrient uptake and transport. Water is the limiting factor in grass growth when the grass plant needs more water than it can absorb effectively from the soil. When water becomes limited, the plant cannot effectively cool itself through transpiration and will wilt.
Grass species differ in wilting tendency and long-term drought tolerance. Some, such as bermudagrass, zoysiagrass, and tall fescue, can avoid wilting for some time because they have deep root systems. However, this advantage is lost if they are grown on shallow soil.
Under drought conditions, Kentucky bluegrass wilts and goes off-color before tall fescue, and if water remains limited, Kentucky bluegrass turns straw-colored and goes dormant.
Perennial rye grass has little tolerance to dry conditions and usually doesn’t survive well in non-irrigated areas. Fine fescues, such as creeping red fescue, chewings fescue, and hard fescue, tolerate dry periods quite well due to their low water requirements.
Water loss is greatest under high light intensity, high temperature, low humidity and windy conditions. 1 inch of irrigation water per week is the standard recommendation for watering when there is insufficient rainfall.
If you have lawns to maintain you can use some common turfgrass management practices to water effectively. For example:
Water during periods of low wind and sun. Night watering minimizes water evaporation, but may increase fungal diseases. Early morning (5 to 8 am) irrigation is a good compromise.
Raise the blade on your lawn mower to increase the grass length. Longer grass blades also shade the soil, reducing the amount of water lost by evaporation.
If your species of turf is not drought tolerant, think about replacing it with one that is. There are many new varieties of tall fescue to choose from that survive well in dry periods.
Do not over-apply nitrogen fertilization. A turf that is too lush requires more water.
Recognize that turfgrasses grown under water stress will not perform as well as those that receive irrigation. Remember, newly installed turf requires more frequent watering than established grass.