Using Water Effectively in Your Landscape

With the lack of consistent rainfall over the past several years (too much in spring and too little in summer and early fall), it is understandable that many people are concerned about using our water supply wisely. I’m concerned, too, and would like to explain the most effective use of water in our landscapes, some of the most efficient methods of watering, and some sources of water that few of us consider.

I say this over and over again when it comes to watering; water slowly, deeply and therefore, more thoroughly. Then, leave the plant alone until it needs moisture again. In doing this, you help to build up a supply of moisture for the plant’s roots and allow, even encourage, the roots to grow deeper. This way the root system can still be cool and moist even when the upper two inches of soil are dry. Incomplete watering keeps the roots nearer the surface of the soil where they are more vulnerable to damage from high temperatures and lack of water. In fact, these roots near the surface can literally cook. That’s why we need to water deeply enough to build up a reservoir of water in the soil capable of keeping a plant’s roots moist for some time. Watering one inch per week should accomplish this in most soils. The roots we are most concerned about watering are those inside and a little way outside of the drip line of a tree or plant. This is where the tree is taking up most of its vital water needs, and we should focus our efforts from about four to six feet inside the drip line to around eight feet beyond on established trees and plants. The lesson here is that watering the trunk of a tree for five minutes does nothing but waste water.

Now that we know why we must water appropriately and where this water should be focused, it is time to take a look at some of the more efficient methods of watering. Soaker hoses that ooze or slowly drip water do an excellent job of directing water toward the root systems and allowing little evaporation. To use these, simply lay or coil the hose around the tree’s drip line in concentric circles or spirals every two feet or so. This will allow the water to soak straight down and also spread sideways beneath the surface. If it has been especially warm and the soil has crusted, turn the hose on and let if run or drip for about 15 to 30 minutes to open the soil up. Then, turn the water off and wait about half an hour before continuing to water. It usually takes about one and a half to three hours for the water to soak a foot or more into the soil, which creates the reservoir. After watering, use a shovel or a stick to check water depth to get an idea of length of watering period that is appropriate for your soil and in that area.

Drip irrigation is another efficient means of watering. With drip irrigation, a series of different sized tubes (the largest being nearest the faucet and the smallest nearest the plants) carries the water to the area of the plants’ root systems. The smallest of these tubes has an emitter on the end, which drips measured increments of water to the roots. The system is designed to be portable, but is most convenient if set up and left in place. The emitters should be placed near the base of the plant, and if a bigger plant is being water, more than one emitter should be used. This way, you avoid a concentration or imbalance of roots. This system works extremely well on new and small plants. Overhead irrigation, early in the morning, from oscillating sprinklers is still effective when left on for approximately three hours in one place. Professionally installed underground irrigation is also effective, but both of these lose water to evaporation. For convenience sake, a timer can be placed on any of the systems.

These are some of the more efficient methods of watering. There are some unique sources of water to think of, also. If we consider the fact that one-gallon of water is wasted every time someone leaves the water on while brushing his or her teeth or runs the faucet until the shower water warms, it’s easy to see where a nation of 300 million people could conserve some water. Therefore, if you want to use what I call “gray water” to water your landscape, there are many places to collect it. One convenient way is to set up a rainbarrel and divert your downspout to it. You can also use the soapy rinse water from your evening dishes. The point is to think about it the next time you see relatively clear water going down the drain.

All of this may seem like extra trouble, but it makes sense to make the most of our resources.