Murray

How much water does a lawn need to stay healthy and green? The general rule of thumb is that most grass requires 2.5 l/m2 of water per day. Research has shown that proper mowing and fertilizing practices encourage a deeply rooted, healthy lawn that efficiently uses its water supply. However, a lawn may need more water if it is under stress from foot traffic, insects or other environmental factors like hot summer days.

Conditions that require higher water use are the same as those found in desert climates — abundant sunshine, low humidity, high temperatures and wind. The combination of these factors can remove between 1 – 5 l/m2 of water per day from the plant and soil system. Conversely, the absence of these conditions makes watering requirements relatively low.

Knowing when to water

Early morning, between 4 a.m. and 9 a.m., is the best time of the day to water. Winds are minimal, the sun is not intense and the water is less likely to evaporate. Watering early in the day also reduces the amount of time that standing water (a catalyst for turfgrass diseases) is on the grass.

The heat is on

While spring showers naturally take care of lawns, hot summer days present the biggest challenge. The 2.5 l/m2 of water per day rule is best accomplished in a few 30-minute watering sessions. Occasional rain may take care of watering needs for a few days, but if it is windy, hot and dry for a long period, you may need to add additional sessions to the daily schedule.

Grass has the ability to go dormant during droughts and will recover nicely when water returns to its system. So, it's acceptable to not water during hot, dry weather – even if the grass begins turning brown. However, after deciding to let the grass go dormant, stick with the decision. Suddenly replenishing the water supply without committing to a schedule will stress the plant and make it more susceptible to damage.

The ultimate convenience

Automatic irrigation systems are very handy for keeping a consistent watering schedule. Just remember that watering too frequently promotes shallow rooting of the grass, which weakens the turf and makes it more susceptible to damage. One of the best devices for regulating water distribution is a rain or moisture sensor that shuts down the system upon detecting moisture. The sensor also prevents the embarrassing scenario and wasting of resources that occurs when sprinklers run during a rainstorm.