Q. What should I know before setting up an irrigation system for my garden? Katie in San Luis Obispo
A. Living as we do in a Mediterranean climate, water is a valuable resource; for some people it may be the largest annual expenditure in the garden. It makes sense to conserve and apply water as judiciously as possible. A wellplanned irrigation system can accomplish this.
It is important to first study the site. Consider your soil type, because water will infiltrate at varying rates. For instance, sandy soils hold less water than clay and need more frequent irrigation.
Know which plants are drought-tolerant as they may be able to survive on seasonal rains, thus requiring no additional irrigation. Take into ac count the root depth of plants; annuals may not need to be watered as deeply as those with longer roots.
Steep sites may benefit from terracing to slow water enough that it soaks into the soil instead of running downhill. Finally, know that sun, shade, temperature, humidity, and wind affect the amount of water that plants require.
A common concern for gardeners is how to effectively irrigate their lawns. A well designed sprinkler system will water evenly without overspray onto sidewalks or driveways. The Lawn Watering Guide for California is afree UC publication at http:// anrcatalog.ucdavis.edu/pdf /8044.pdf . Gardeners can use this to determine the output of their sprinklers and learn the suggested frequency and duration to water each month of the year.
Another helpful resource is the San Luis Obispo County Water-Wise Landscaping site at www.slowaterwise landscaping.com/Garden -Resources. In addition to information on irrigation systems, gardeners can learn more about water conservation by mulching and grouping plants with similar needs.
To learn more about setting up a system and to see a demonstration with various irrigation components, attend the Advice to Grow By seminar at the Garden of the Seven Sisters, 2156 Sierra Way, San Luis Obispo, from 10 a.m. to noon Saturday.
GOT A GARDENING QUESTION?
Contact the University of California Cooperative Extension Master Gardeners at 781-5939 on Mondays and Thursdays from 1 to 5 p.m. in San Luis Obispo; at 473-7190 from 10 a.m. to noon in Arroyo Grande; or at 434-4105 on Wednesdays from 9 a.m. to noon in Templeton. Visit the UCCE Master Gardeners website at http://ucanr.org/sites/mgslo or email firstname.lastname@example.org .