In climates that have long, hot, dry summers, the turf varieties most commonly used are perennial grasses that not only thrive in hot weather, but also develop deep and extensive root systems. These properties can be exploited to reduce water consumption in normal years, and to minimize it during drought years. With the suitable variety and correct irrigation practice, the lawn may look poor under the minimalist regime, but its root system should remain intact, allowing the grass to appear as it should when more water is available in better years.
Under regular circumstances, the amount of water calculated for any given irrigation, is the volume required per day, multiplied by the number of days between each watering. This interval differs for heavy, clay soils that retain water well, as opposed to light, sandy soils, which do not. Lawns growing in sandy soils may need watering every 3-5 days, while in clay soils the interval could be between 7-14 days. It is preferable to extend the interval as far as possible in order to encourage a deep root system, assuming that the species chosen has such properties. Lawns grown in this way are more able to withstand drought and reduced quantities of water.
Here is a way of using less water each time. Let?s say for example that we water our lawn every 10 days, and set the irrigation timer accordingly. The lawn appears green, lush, and healthy. Instead of setting the taps to open on the tenth day, we wait until the first signs of stress exhibited by the grass, which occur, say, after 12 days. From now on, we apply the same quantity but for 12 days instead of ten!
Now let?s take this a step further. Instead of watering when the first signs of stress appear, we wait until the grass really starts to brown-off. This may happen after a further 7-10 days or so, but the quantity supplied at the next watering is still that which is appropriate for a ten-day interval. The grass may look dire during that period, but it should recover after being irrigated, while little or no damage is inflicted on the roots. This is how a lawn can be saved during a drought year.
It must be made clear however, that such a regime is not suitable for all lawn types. To reiterate, it works with warm climate, perennial species, preferably with those that grow by rhizomes, (stems that grow horizontally, under the ground) such as the many varieties of Bermuda grass, Kikuyu, or Zoysia. Some of these examples may not be ideal from every point of view; Kikuyu for instance, is feared as a noxious weed in many places, but here we are only referring to water conservation. It is also assumed that the method presented here should only be attempted on established lawns.
My name is Jonathan Ya’akobi.I’ve been gardening in a professional capacity since 1984.I am the former head gardener of the Jerusalem Botanical Garden, but now concentrate on building gardens for private home owners.I also teach horticulture to students on training courses.I’d love to help you get the very best from your garden,so you’re welcome to visit me on http://www.dryclimategardening.comor contact me at firstname.lastname@example.org