When you want a drink of water, you can walk over to the faucet or grab a bottle.

Plants don’t have that option - they depend on the water you give them, or what falls as rain. How much water do plants need, and what’s the best way to get it to them? A general rule of thumb is one inch of water per week. Plants that get an inch a week will certainly survive, and will probably thrive . . . unless it is blazing hot, unless the soil was dry as a bone to start with, and unless the soil is very sandy, so use your judgment.

• In extremely hot weather, soil dries out fast and may stress your plants.
• If the soil was allowed to dry out, an inch of water will hardly reach plant roots, and may just run off on the baked surface of the soil.
• Very sandy soil can’t hold water, so it just sinks down below where roots can reach.

So what’s a gardener to do for thirsty plants? First, get a rain gauge. This is a cheap (about $5) plastic funnel-shaped container with marked inch gradations down the side. Mount it in your garden attached to a stake. Don’t allow anything to get between it and the sky (such as a giant sunflower). When it rains, water collects in the gauge, and you can read how many inches of rain - or what fraction of an inch - fell. Now you know whether your plants need a light watering or a thorough soaking.

Next, work a lot of compost into your soil. Compost helps hold water where plants can reach it. Compost-enriched soil takes longer to dry out, even in hot weather. It also feeds nutrients to your plants, and helps to prevent diseases.

Lastly, but most important, get a drip irrigation system. Plants need water around their roots, but water on their leaves is harmful and can cause diseases. Overhead watering systems, such as sprinklers, waste a lot of water - about 70 percent of sprinkler water is lost to evaporation and never reaches the plant roots. If you want to get fancy, you can buy a soil moisture meter. Alternatively, you can learn to do what experienced gardeners do - stick your finger down into the soil to see if it is damp below the surface. Damp soil feels cool. If you want to protect your fingernails, use a small trowel to see whether the soil an inch or two under the surface is damp. With a rain gauge, it is easy to see how much water fell on your garden. Figuring out “an inch of water” with an irrigation system involves a calculation of gallons per hour, drip rate, and the area to be watered. But as a rule of thumb, with the drip irrigation systems EECO Farm made available to gardeners in 2004, it takes two or three hours to deliver an inch of water.