The installing of a professional, automatic irrigation system is a pre-condition for successful gardening in a dry climate. Less obvious perhaps is that such a system is an essential part of proper water management, which aims to use this precious resource as efficiently and responsibly as possible. As a suitable electronic water timer is a vital ingredient of any decent watering system, the question arises as to which type has the features that help the gardener turn the goal of efficient water management into reality.

To answer that, we need to be clear as to what constitutes “efficient water management.” The correct use of water is similar to managing a budget. One should know how much is available for the year, and to plan consumption accordingly. For this reason, groups of plants with differing water requirements should be watered from separate taps. Clearly, established trees and shrubs which need two or three deep waterings a year, need to be independent of annual flowers that may need watering every three days or so.

It follows then, that the first requirement of an irrigation computer is to have at least as many stations as different plant groups. The more taps (stations) available, the greater the flexibility, and so the easier it becomes to supply the exact quantities required by the plants, and according to the appropriate interval between each watering. Therefore, the irrigation timer should not only feature different watering durations for each tap, but different frequencies as well. In this respect, the best timers are those that entirely separate each tap from each other, so that both duration and frequency can be independently programmed for each station.

Another important aspect to a water–conserving regime is to irrigate as infrequently as possible. Plants in heavy, clay soils generally grow better in the long run with occasional but deep watering, as opposed to shallow, frequent irrigation. It also helps to protect the soil from the potentially devastating affects of increasing salinity and the consequent creation of sodic soils. Watering infrequently develops drought-resistant properties in the plants, thereby making it possible to defer watering during the “in-between seasons” such as spring and autumn.

Electronic water timers should therefore allow for this. Timers that force you to water once every few days not only waste more water, but do not necessarily provide for optimal growing conditions for the garden plants either. Look instead for products that contain schedules of up to 30 days or more, so that the option of watering infrequently exists.

Every so often, some cheap product is pushed on to the market. Beware of these, for not only is their reliability liable to be doubtful, it is unlikely they possess the features necessary for efficient water management. Ultimately, the best irrigation computers operate according to the volumes of water that the system emits. These are extremely expensive however, and are generally practical for public or municipal gardens.