Making the Most of Summer Watering  

It is no secret that plants need water to survive, but it can be a little tricky to determine when to water and how much to water. When you throw in the effect weather patterns can have on plant irrigation, it may look like you’ve got a real puzzle. But don’t panic; understanding the basics of a plant’s need for water and following some simple guidelines can take the mystery out of landscape watering.

Using water effectively (today, more than ever is critical) in your landscape actually begins with proper planting. Well-prepared soil allows water and air to move through the root system and means that water is more easily accessible to the new plant. Since roots grow sideways and not down, place new trees approximately one to two inches higher than surrounding ground level. This means that the root system doesn’t have to grow up to reach the best combination of air and water in the soil. To accomplish this, leave the center of the planting hole slightly higher (in undisturbed condition) to avoid having the root system settle into soft soil after planting. Take care not to plant too high, though. Planting on a mound can cause root systems to literally bake in the hot sun. When finishing a planting job, use excess soil to form a saucer around and directly above the root ball. This channels the water toward the roots and allows it to soak down through the entire root system. Finish off the job with an appropriate mulching material, applied to a maximum depth of two inches, to help maintain the soil’s moisture level.

When plants have a strong start in the landscape, providing adequate water is relatively simple. The guiding principle for landscape watering is to water slowly and deeply, and thoroughly and then wait until the plant needs to be watered again. You can determine when this is necessary by using a crude, but effective, stick test. Simply take a one-half to three-quarter inch diameter dowel rod and push it into the ground to 8-12 inches deep to see what is happening in the soil around the root system. If the stick’s wood darkens and soil pieces cling to it, it’s probably not time to water again. If the stick comes out clean - no discoloration or particle matter, conditions are dry, and you should water immediately. Check sites all over your landscape. You’ll find that different areas have different irrigation needs and you’ll be able to develop a watering cycle that best suits the plants in different locations in your landscape.

When watering established plants and trees, concentrate your efforts on the hair root zone. This begins about three to four feet from the trunk and extends to the drip line (edge of foliage) at least six feet beyond that drip line. Try to provide about an inch of water per week. This amount of water will soak down approximately eight to twelve inches to where the plant can make the most use of it. This also helps to build an in-ground reservoir of moisture that is beyond most of the effects of heat and rapid evaporation. In my soil, it takes about three hours to deliver an inch of water, but that will vary with every yard and water delivery system. Set up some high sided pans in the irrigation pattern and check for 1 measured inch in each.

Plants go through two stages of drought before death. Temporary wilting usually occurs inmid-late afternoon and vanishes overnight and no additional water is needed. Wilting that doesn’t dissipate overnight indicates that the plant needs water immediately. At this point, if you don’t provide immediate and adequate water, the plant may die. It’s that simple. Regular inspection of your landscape know the variations on your site and to spot problems long before you lose a plant.

Summer watering isn’t a mystery, but it is a necessity. And with these basic guidelines, you can give your plants exactly what they need to survive a long, hot summer and even be in better shape to go through the next winter.