How often should I water my plants? Why there’s no good answer in North Texas

I was watching a water conservation ad from one of the local supply districts on television the other night. They were stressing the importance of using native plants, and just as those words tumbled out of the sound bar, I saw the leaves of glossy abelia flash over my screen. Well, pardner, that baby ain’t native to Texas!

It set my mind to thinking about the missteps we make as we water our plants. I’m going to lay out short facts that are important. Some may rattle a few cages. We may even cover some old topics. See what you think.

▪ It’s better to water less often but to soak the soil when you do. That encourages plants’ roots to grow more deeply.

▪ The best time to water is early morning (2 a.m. to 10 a.m.). Water pressures are best then and humidity is highest, so there will be least loss to evaporation. Winds also tend to be lower. Evening watering promotes disease.

▪ Drip irrigation is a fine concept, but it takes a longer time to saturate soil with drippers. Pay close attention to your plants’ needs and be sure you’re soaking the ground deeply — not just on the surface.

▪ Learn to recognize your plants’ symptoms of drought. Many wilt — it’s easy to recognize those. Others change colors, often to a glossy, darker green. St. Augustine is a good example, plus its blades fold lengthwise.

▪ Some plants give you very little clue of their extreme need for water. Hollies and magnolias are examples. Their leaves are leathery. They undergo subtle changes in color, but by the time it’s particularly noticeable you may have lost the plants.

▪ The soil beneath a plant will give you good clues. If you’re able, stick your finger into it. If it’s moist you’re probably fine, but if it has a hard surface and is developing cracks, it’s time to water.

▪ Our irrigation water for most parts of North Central Texas is even more alkaline than our native soils. That works against our acid-loving plants like hydrangeas, gardenias, azaleas, camellias and loropetalums.

▪ There is no good answer to the question, “How often should I water my plant?” There are too many variables. You must factor in soil type, plant species, sun/shade, slope (before runoff), and how long the plant has been growing in the location. (New plants will need to be watered much more often.)

▪ Newly planted trees and shrubs should be watered every two days from May through September for their first two summers. They’re growing in loose, lightweight potting soil to keep shipping costs down. That soil will dry out much more quickly than the soil we have in our yards. Once they produce roots into the surrounding soil in their second and third years you can begin to turn things over to the sprinklers.

▪ Robust weeds use water at a much faster rate than our desirable landscape plants. That’s why it’s so critical that we keep weeds under control in our flowerbeds and vegetable gardens.

▪ Mulches serve many functions. By smothering weed seedlings from sunlight they prevent germination and growth of the undesirables. Those that do sprout are easily cultivated out with a sharpened hoe. Plus, mulches reduce soil-to-air contact, and that conserves moisture greatly. I personally prefer organic mulches such as compost, finely ground pine bark and well-rotted manure.

▪ It’s probably best to avoid nitrogen fertilizers as temperatures reach their hottest during the summer. Nitrogen promotes vigorous new growth, and that may come at a time that plants can’t pull water through fast enough. If in doubt, wait until late August or early September before feeding your shrubs and turf.

▪ Patio pots bring their own special issues. This far into the growing season those plants may be quite rootbound. You may need to consider watering two times per day if you find that your plants are dry when you get home from work.

▪ When it comes to houseplants, water meters aren’t very good investments. They aren’t especially accurate. Again, your fingers and thumbs will do a better job of telling you when the soil is dry and needing to be irrigated. Look, too, at the edge of the potting soil. When it begins to pull away from the side of the pot it’s beginning to dry out.

▪ When you water a potted plant, water it thoroughly so that it drains out the hole in the bottom. That will ensure that minerals don’t accumulate to harmful levels.

▪ If you have large containers sitting directly on top of the ground, be forewarned about roots that could grow out the drain holes and plug up the pots. They can stop drainage and end up causing loss of the plants. It’s best to elevate those pots an inch or so off the ground so that roots will be “air-pruned” as they try to grow out through the drain holes.

▪ And to close out on the same theme with which we began, don’t assume that just because a plant is native somewhere in Texas that it’s going to be a great choice for your landscape. My pal Siri tells me that Texas, were it not just a state, would be the 39th largest country in the world. That might explain why plants that are native to one corner of our big state won’t grow in another. Ask your nursery professional to show you only plants that are “adapted” to your locale and you’ll be far ahead.

This story was originally published July 28, 2023 at 6:00 AM.