Water deeply and only when necessary
What are the consequences of a lack of water?
A lawn goes into dormancy when it doesn’t get enough water – in other words, it stops growing. The grass leaves and stems die and turn brown, but the underground parts (rhizomes and roots) are still alive, just waiting for rain. Generally speaking, a well-maintained lawn can survive a summer drought without watering. However, it will stay lush and green all summer long, and stand up better to trampling, weeds and insect pests, if watered properly.
How often to water?
There is usually no need to water a lawn before late June. After that, you should do so fairly regularly, allowing yourself to be guided by how dry the soil is. When you do water your lawn, be sure to water it deeply. If there is no rain, give it 2.5 cm of water a week – that means running a sprinkler for a few hours. A good way to tell whether you’re using the right amount of water is to place four or five similarly sized containers around the lawn; turn off the sprinkler when there is 2.5 cm of water in the containers.
Usually, a lawn grown on sandy soil needs to be watered for less time (the water penetrates more easily) but more often (the soil dries out more quickly) than a lawn grown on clay soil. To soak the soil thoroughly, it is best to use a fine, light spray, especially on clay soil or steep slopes, which can’t absorb too much water at one time. If you notice any runoff, stop watering for a while and start again later.
The best time to water?
Avoid watering around midday on hot days, because up to 50% of the water will evaporate before it soaks into the ground. It is best to water your lawn in the morning or, failing that, in early evening. The blades of grass need time to dry before nighttime or they will be susceptible to fungal disease.
Will lawns turned yellow following a dry period become green again?
YES. Thanks to a dormancy mechanism, grasses stop growing during a period of drought. The lawn can be completely yellow for several weeks but turn green again after adequate rain (several hours – not just a shower) and as soon as climatic conditions return to normal. Avoid all undue traffic on the lawn during this period, however.