With 97 percent of the Earth's water supply too salty to be used by humans, and 2 percent of the supply locked up in ice caps, conserving the 1 percent of potable water is always important. It becomes even more significant during drought years, says Contra Costa Master Gardener Steve Griffin.

Griffin, an irrigation wizard who has masterminded the drip irrigation system at Our Garden, laid out the basics in this week's class.

Stop the waste

  • The most important thing you can do to conserve water is to make sure your irrigation system isworking properly.

  • Check your sprinklers to make sure they are going on the lawn, not the pavement. Replace broken ones or those not delivering where you need the water.

  • Don't just set your irrigation controller and walk away. Water needs differ with the season and the growing conditions.

  • Use organic fertilizers instead of synthetic. Organic fertilizers will improve the soil's biology and fertility; water will be able to move through this healthy soil to get where it is needed.

  • A build up of synthetic fertilizers will eventually kill the microbes in the soil, harden it and send water rolling off instead of sinking in.

    Smart controllers

  • Smart controllers that connect with weather stations and satellites can take a lot of pressure off gardeners. By using technology, the controller will establish the best times to irrigate based on weather conditions, your soil type and what, in general, you are growing.

  • The controllers can be pricey and there is a yearly fee for connecting to the service, but you likely will earn the money back in water bill savings.

  • If you can't afford a smart controller, or want to be a hands-on gardener, you can become the smart controller, Griffin says.

  • Learn about your soil type and be proactive, digging down to make sure the water is going where it needs to, and programming your simple controller to match watering needs.

    How long do I water?

  • There is no simple answer to that question, Griffin says, because it depends on your soil type, slope, location and what plants you are growing.

  • At Our Garden, during the peak of the season, we put 3 inches of water on the beds every week. That 3 inches is delivered at about an inch, three times a week.

  • Learn how fast water is absorbed in your garden or lawn. If you have compacted soil or have a slope, water may start running off before it has much of a chance sink in. To counter this, water multiple times for short periods. For example, you may want to set your timer on your lawn irrigation to come on for 5 or 10 minutes at 2 a.m.; then for another 5 or 10 minutes at 3 a.m., and so on.

  • Improve your soil by adding composting and mulching. Healthy soils require less water and retain it better.

  • For compacted soil under lawns, aerate to improve water absorption.

    Know what lies below

  • Looking at the top of your soil won't tell you much about what's going on beneath it. Dig down with a trowel, a shovel or soil probe to make sure water is soaking in, not just staying at the top.

  • If you can wring water out of a handful of soil, you are overwatering. If the soil is dry and won't clump, you need to water more deeply.

    Drip irrigation

  • Drip is the most efficient irrigation system you can have, and advances in the systems make them easier to install and maintain.

  • When buying parts for a drip system, make sure they all come from the same manufacturer, which ever one you prefer. Mixing and matching brands can lead to incompatibility issues.

  • Always filter your drip lines to prevent clogging, and install the filter in between the water source and the pressure reducer.

  • Always use a pressure reducer to keep pressure to 30 or 40 pounds. Higher than that will defeat the purpose of drip irrigation and can damage your emitters and system.

  • Always flush the delivery lines before adding the emitter tubing.

    What's the capacity?

  • To know your flow, or capacity, take a 5-gallon bucket and time how long it takes to fill it from an fully open faucet. For example, if it took 60 seconds to fill the bucket, you'll know that your capacity is 300 gallons per minute (5 gallons times 60 seconds).

  • Knowing your capacity will determine how much water you can deliver to your beds and help you configure the system.

    For more information, try these websites:

  • Contra Costa Water District, www.ccwater.com

  • Water Savers irrigation stores, www.watersaversinc.com

  • Drip Works, for a capacity calculaor and designs, www.dripworks.com.

  • Contra Costa Master Gardeners help desk, http://ccmg.ucdavis.edu

    Update

    Last year, Our Garden donated more than 12,000 pounds of produce to the Monument Crisis Center in Concord. So far this year, we've donated 1,213 pounds thanks to our winter garden.

    Our Garden

    Our Garden offers free gardening classes 10 a.m. to 11 a.m. every Wednesday, through October. The garden is located at Wiget Lane and Shadelands Drive in Walnut Creek. Master Gardeners are available to answer your questions and diagnose disease and pests, and there is a wide variety of plants for sale.

    Next time in the Garden: Attracting birds to your garden with Joanie Smith, owner of East Bay Nature.