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Young Plant Water Needs

The temperature spiked to the mid 90’s this past week in Casper, prompting gardeners to worry about their newly planted trees from this spring. I’ve received worried email notes, photos on smart phones, phone calls and samples brought in. It all leads to one thing, improper irrigation technique.

Last week I wrote about irrigating your landscape to a depth of twelve inches and then maintaining a system of balancing your irrigation frequency for the health of your mature landscape. That article didn’t get into the morning paper but you can read it online at trib.com. So let’s visit about irrigating young plants, namely trees, but the same thing goes for irrigating your tomatoes.

When plants go into water stress (not enough water to support bodily functions) the first reaction of the plant is to get droopy. If water isn’t applied then, the plant shuts down water supply to its furthest extremities—its leaves.

The leaves turn brown at their tips. Still, if water is not applied, the edges of the leaf continue to brown up, then the whole leaf, followed by the twigs, so on and so forth, always working from the furthest extremities downward and inward.

That is exactly what I’ve seen this past week. Gardeners are applying too little water too infrequently and their trees and tomatoes leaves are frying up.

At my garden center I have trees in pots that are drinking 20 gallons of water a day. They are actively growing; coupled with the heat that’s a lot of water. To put that into perspective, my staff and I are applying 160 pounds of water daily (one gallon of water equals 8 pounds). We space out our irrigations up to six times a day.

Obviously, what we do to irrigate at the garden center won’t work for most gardeners—that’s just too intensive. So what can gardeners do to maintain their young plants’ water needs?

The first thing I would have gardeners do is to get a moisture meter. Moisture meters have a stem that is put directly into the soil at about four inches deep. They immediately read the water content in the soil. Most moisture meters have a scale of one to four or one to ten, with one being critical to water while the upper numbers means there are adequate amounts of water in the soil.

What moisture meters really do is calibrate a gardener’s irrigation technique. For young plants with limited root systems trying to live in Wyoming, gardeners should check the soil twice a day, morning and evening and irrigate accordingly.

The good news is this irrigation regime is a brief time in the plant’s life. Roots get bigger and expand into the soil where more water lies. To me it’s the equivalent of the needs of a young puppy vs the needs of a five year old dog. The puppy needs much more attention.

All is not lost if your plants have experienced water stress. By getting into the proper irrigation zone, new growth will reemerge and life resumes.

Originally published in the Casper Star-Tribune, July 5, 2015


Throughout this site, the following are used as guidelines for watering established plants: