I correspond with a group of serious gardeners located mostly on the East Coast. In summertime, these folks get pretty nervous when more than a couple of weeks go by without rain. There is talk of drought and water restrictions.

They are bemused when I explain that for Napa Valley residents, summer drought is a way of life. Hillsides and open spaces are green in winter and brown in summer. The rain ends around May and doesn’t resume until perhaps October or later, and our gardens and lawns are totally reliant on the attention and generosity of the gardener to provide that vital resource.

Oh, and incidentally, rainwater is free. We pay for the stuff that comes out of our hoses and sprinkler systems.

In California, we use more water on our landscapes than we do for showers, laundry and all other uses combined. A homeowner who wants to use water more responsibly can employ myriad techniques and strategies and still have a pleasant and colorful garden.

Start with the design or renovation stage. I often see homeowners tear out lawns only to replace them with a new lawn of the same size. Lawns use lots of water and fertilizer and are not necessarily a low-maintenance option for your outdoor spaces.

If you must have a lawn, consider shrinking the size and using shrubs combined with drought-tolerant ground covers instead. Always plant sod or seed varieties that are suitable for our climate. Many national chain stores and even local garden centers still inexplicably carry Kentucky Bluegrass seed blends that guzzle water and dislike our arid summers. Plant a turf-type fescue instead, which can take the heat of summer, needs less water and is therefore better able to resist disease and other maladies.

Plant in zones, grouping thirsty plants together. Established shrubs typically need only about three inches of water a month to stay healthy and attractive, while flowers, vegetables and other ornamentals may require substantially more moisture. Designing a potager-type area for edibles, annuals and roses is one way to combine those plants that appreciate more frequent irrigation.

Mulching is a great tool for water conservation and provides many other benefits as well. A two- to four-inch layer of composted material inhibits weed growth and improves the soil structure as it breaks down. I apply mulch every spring after the rainy season and add a bit more in mid-to-late summer. The mulches I use are primarily forest products that can consume nitrogen as they break down, so I always apply an organic nitrogen fertilizer such as alfalfa meal at the same time. Mulch also gives your garden a tidy and well-groomed appearance.

Be efficient with your irrigation practices. Shady areas don’t need as much water as areas of full sun. If you are using an automatic controller, be sure to adjust the settings to reflect the weather patterns. I don’t usually water anything but container plants until May, unless we have a dry spring.

Check your system to see if you are experiencing any run-off. If so, use more frequent but shorter cycles. In non-lawn areas, cultivate the surface of the soil and mulch for better water penetration. Make sure your sprinklers are timed to run when there is little or no wind. We’ve all witnessed a neighbor’s irrigation water blowing down the street and evaporating before it ever hits the ground.

Learn about and use drought-tolerant plants. Every garden center has colorful and attractive plants that require little summer water. A knowledgeable nursery professional can advise you about those that will perform well in your specific garden setting.

The City of Napa is presenting two more free workshops in its popular “Wise Watering” series. Attendees will receive a CD-ROM titled “Water Wise Gardening in the Napa Valley.” Workshops will be held at the Pelosi Building in Kennedy Park from 6:30 p.m. to 8:30 p.m. On Thursday, Sept. 20, the topic will be “Soils, Mulches and More.” On Thursday, Sept. 27, the topic is “Perfect Plant Picks.” Call 257-9309 to reserve a space. Either one of these informative sessions will be time well spent if you would like to learn more about conserving our most precious resource.

Contact Master Gardeners at the UC Cooperative Extension office, 1710 Soscol Ave., Suite 4, Napa, 253-4221, or toll-free at 877-279-3065. E-mail your garden questions by following the guidelines on their Web site www. master gardeners.org. Click on Napa, then on Have Garden Questions?