How Often Should Plants Be Watered?

You can insert almost any kind of plant into that question. I’ve probably been asked it. Unfortunately, there is no one correct answer. But, we do know that we need to conserve. And, water conservation begins with selection of plants that are well adapted to your area — plants that are known to be water-efficient. It doesn’t necessarily mean cacti and yuccas. It just means you should avoid plants that suffer abundantly under your Texas conditions.

• Learn to recognize drought symptoms, and watch for them daily. Just because a plant is wilted at 3 p.m. doesn’t mean that it’s dry. Some plants, when exposed to sun, struggle in mid-afternoon. Check the soil to be sure it’s beginning to dry.

• If only a small area or a handful of plants is dry, use the water hose to irrigate that space. There’s no point in running the sprinkler system for the entire lawn and landscape if only one area is dry.

• Encourage deeper root growth by soaking the soil, then letting it become dry an inch or two down before you water again.

• Use mulches to reduce the rate at which water evaporates from the soil’s surface. Mulches also reduce weed growth, further reducing water consumption.

• Adjust your sprinkler timer so that each station will need to be watered at approximately the same intervals. That may mean running one shady station with spray heads for only 10 minutes while a large turf area with impact heads is watered for 30 or 40 minutes. Your goal is to apply about 1 inch per week, but to do so in a way that the water won’t run off.

• "Smart" controllers take a lot of the guesswork out of irrigation. They monitor the weather, and they balance that with the types of plants you’re growing, the soils and slopes, sun or shade — all the environmental factors. These controllers save tons of water — and money!

And, finally, my best attempt to answer the question as it has been presented:

• If it’s 90 degrees, you should be able to go a week between irrigations (assuming no rain).

• If it’s 95 degrees, the interval probably shortens to 5 days if you’re watering correctly.

• At 100 degrees you’ll probably need to water every 4 days.

• At 105, the interval shrinks to 3 days.

(Of course, all of those intervals are completely dependent on water curtailments that may be in play in your area. They vary from area-to-area and even city-to-city.)

Potted plants don’t use the same formulas. They’ll need water more often than their in-ground counterparts.

New trees and shrubs should be hand-watered halfway between sprinkler irrigations to be sure they don’t dry out.

Turf that is less than one month old should be watered lightly once or twice daily for the first two weeks, then every day or two for two more weeks, then as needed forever.

Posted by Neil Sperry
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