Water is a precious commodity in Southern California, even following a winter with record rainfall. While our native plants are adapted to scant and seasonal rain, most of the plants we use in our gardens must be cared for with close attention to how much and how often we water.
Our goal should always be to water as infrequently as possible for as long as necessary to allow water to reach the roots of the plants. The amount of water and the time it takes to apply varies considerably with the type of soil. Sandy soils allow water to reach roots quickly but dry out quickly, too; clay soils take longer to wet but retain the moisture for much longer. Trial and error will help you learn the best schedule for your garden. A moisture probe, available at all local nurseries, can help you determine whether the water has adequately penetrated the soil.
Watering with a hose, except in the case of potted plants, simply doesn't work.
The most effective way to deliver water efficiently and thoroughly is with an in-ground irrigation system, regulated by an automatic timer clock. If the clock has multiple programming options, you will be able to water plants with differing moisture requirements on individualized schedules. For example, plants with southern and western exposures can usually be watered on one program since both receive the hottest sun of the day and dry out more quickly than plants in other locations. On the other hand, plants with northern exposures will receive much less direct drying sun and are better irrigated on a program that waters less frequently. Shallow-rooted lawns and ground covers needing frequent but shorter irrigation cycles can be on still another program. If annuals are irresistible, they might be planted next to a lawn since they, too, are shallowrooted and need frequent watering. Any area that is predominantly California natives or South African bulbs (next month's subject) should be on a zone by itself. These plants do best with infrequent summer watering.
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There are many irrigation systems available; they can mostly be categorized as conventional (in ground pipes, a variety of above-ground heads) or drip (above-ground soft pipe with spaghetti tubing or soaker hoses to individual plants). I personally think conventional systems are much less trouble-prone and easier to use. When a conventional system part breaks, a geyser usually announces the problem; when a drip emitter is clogged or inadvertently moved (by a rake or an animal) away from the plant it's watering, the plant can suffer for a long time before the problem is noticed.
Whatever system you choose, don't forget to adjust the timer clock seasonally to accorru;nodate changing day length and supplemental water from the sky! Some winters I have been able to turn off my sprinkler system for several months.
For more detailed information, look at two interesting websites. One is www.bewaterwise.com. Note particularly the Watering Calculator that can be found by clicking on "About the Watering Index." The other is www.thegarden.org. Click "Links" in the left-hand column for several useful sites.
Finally, don't forget to provide a birdbath full of fresh water for our resident feathered friends. Summer is long and dry for them, too!