Days when temperatures climb into triple digits followed by evenings with fast-moving thunder storms can leave beginning gardeners unsure about whether or not to add supplemental water to their vegetable gardens.

The general rule of thumb is that plants need about one inch of water a week either from rain or irrigation or a combination of the two.

The amount of water can vary depending on the type of soil in the garden, but the objective is to wet the soil to a depth of 5 or 6 inches and not water again until the top few inches begin to dry out.

“Your garden needs to be watered deeply,”says Henrico Extension Agent Lisa Sanderson. “And that requires some time.

“Some people think sprinkling water with a hose for a few minutes and wetting the surface of the soil will be enough,”she adds,“but deep watering is not something you can do for 10 minutes and be done.”

Taking the time to water plants deeply can make them more resistant to droughts because the plants develop deep roots.

“Watering a little bit every day encourages shallow roots,” says Sanderson, “So plants dry out quicker. And watering every day helps surface seeds, which are usually weeds, to germinate and grow.”

Sanderson cautions that every garden is different, so gardeners need to check their soil to see when to water. Sandy soils may need to be watered more often, while a clay soil can hold moisture longer. Organic matter that you can add by incorporating it at tilling or by top dressing plants with compost can help soil hold moisture.

“You can use a rain gauge to see how much rain water your garden is getting,” says Sanderson. “Or use a soil meter to see how dry the soil is.”

“Fingers are also wonderful things to check soil moisture,”she adds. “Or use a trowel to pull back some soil and check for moisture.”

The best time to water is in the morning when cooler temperatures mean less water will be lost to evaporation. Watering early also allows foliage that gets wet to dry before nightfall.

“It’s better to water at the roots,”says Sanderson. “More water gets to the plant, and you have fewer issues with disease caused by moisture on the leaves.”

If time is an issue, busy gardeners can use soaker hoses that allow water to slowly seep out all along their length. Placed at the base of plants and left on for sufficient time, soaker hoses can provide the deep watering that plants need.

“It’s also a great idea to mulch your plants,”says Sanderson. Mulch conserves moisture in the soil by slowing evaporation and can prevent backsplash on leaves during watering. Plus mulching helps to control weeds that compete for the soil’s moisture.

Sanderson adds that these watering principles also apply to landscape plants.

“Usually, established plants are fine,” she says,“but when you have these hot, hot days, it’s a good idea to keep your eye on your plants to see if you need to water.”