Introduce your customers to irrigation
Few areas in North America receive so much rainfall that irrigation isn't necessary. In most regions of the United States, turf needs extra water more than 35 percent of the growing season, making it essential for you to have some type of irrigation program.
Hose-connected sprinklers aren't practical on large lawns (more than 5,000 square feet). Therefore, a permanent, underground system is your best option. Grounds of all sizes are generally made up of turf, trees and shrubs — each having different water requirements. A well-planned, permanent, underground system can supply the proper amount of water to meet the water needs of the various aspects of your grounds.
It's important that your lawn-care customers understand the importance of this. In many regions, turf may be able to “get by” in some years without much irrigation. This can make some of your clients reluctant to invest in a permanent sprinkler system, because it leads them to believe that it's not absolutely necessary. However, you must explain to them that, if your applications are to benefit their turf in the intended way, drought stress must be minimized.
This can be a selling tool for you, if you offer irrigation installations. However, even if you don't, your customer will be far happier with your lawn-care results if they irrigate the turf properly. A bit of customer education can go a long way, which is why many applicators leave door hangers or other literature after they treat a lawn to remind customers to irrigate. Consider the following guidelines, which are written in non-technical language and can give your customers a reasonably good method for evaluating irrigation needs with minimal experience and no special tools.
When to irrigate
Turf's appearance will tell you when you need to irrigate. A dull coloration is an obvious visual cue. Stressed turf may also wilt. This may not be immediately apparent, but turf that is wilted will not spring back after being stepped on.
Even untrained people can easily identify drought-stressed turf. However, they must remember to actually look. High daytime temperatures, bright sunny days and low relative humidities cause lawns to use the greatest amount of water, so tell them that they should pay closer attention to turf during this type of weather. Of course, during periods of cloudy, overcast weather, low daytime temperatures and high humidity, lawns will use less water.
A screwdriver is an easy-to-use tool that they can use to roughly gauge soil moisture and depth. When the top 6 inches of soil is dry, the screwdriver won't penetrate the soil easily. It's best to irrigate turf before it gets to the point of severe stress, so tell clients that, if they're having trouble driving a screwdriver into the ground, it's probably time to irrigate.
How much to apply
The majority of turfgrass roots are in the top 6 to 8 inches of soil. This is also where they take up much of their water. They do not store resources in large taproots as do some landscape plants. Thus, irrigation must be designed to efficiently apply water to the topmost layer of the soil.
Customers need to understand that applying water to turf faster than the soil can absorb it will result in waste. When this occurs, water will either flood an area or run off to non-target areas. They also must understand how critical it is that newly established turf is watered without fail.
Irrigation systems for ornamentals
Many landscape plants, trees and shrubs often have a deeper root system than turfgrasses. For this reason, you should irrigate them differently than turf. Trickle or drip systems and bubblers are two other irrigation methods (besides standard spray heads) for landscapes that are better suited to ornamentals than turf.
Trickle or drip systems. These systems apply water to the soil at a low flow rate. Trickle irrigation is generally used on landscape plants, such as shrubs and flowers, that are shallow rooted. It is popular in dry climates where water slowly sinks into the soil. This method has the advantage of irrigating the soil around the plant but saving water between widely spaced landscape plants. It isn't recommended for lawn irrigation.
Bubblers. These devices flood a specific soil area more quickly than a trickle system. They are used on large landscape plants that have or will have a deep root system. Bubblers provide deep watering when the plants are contained by soil that is shaped similar to a watering basin.
You already know how important irrigation is. Educating your customers about it is equally important. Not only will it make your efforts more effective, it may lead to add-on sales as customers realize the benefits.
Dr. David M. Kopec is a professor of turfgrass science at the University of Arizona (Tucson, Ariz.).
GUIDELINES FOR NEWLY ESTABLISHED TURF
A newly established lawn should be irrigated lightly and frequently enough to keep the upper soil layer (1 inch of soil or less) moist. This usually means short-but-repeated irrigations during the warmest parts of the day, especially in warm-season regions. It can be difficult to establish turf in such areas without an automatic timer. In cool-season areas, turf is usually established during spring and fall when rain is more plentiful and when turf may not require daily supplemental water. But you must be prepared to water in case a dry spell occurs.
Decrease irrigation to one time per day (but with slightly more water, 0.25 inch) once turf has grown to about 2 inches, or when the roots have started to knit so the sod doesn't easily pull up by hand. Repeat this daily irrigation for an additional 3 to 5 days. Then, skip a day between irrigations, applying 0.30 to 0.50 inch of water. This will wean the turf off the previous, more frequent, irrigation schedule. The result is a deeper root system and a healthier lawn that can better withstand hot weather conditions.
IRRIGATION GUIDELINES FOR MATURE TURF
Mature turf has different needs than seedling turf. The following guidelines are useful for homeowners.
Apply enough water to wet the soil to a depth of 6 to 9 inches with each irrigation. To reach this depth, a sandy soil will require about 0.25 inch of water; a soil with some sand and clay will require about 0.5 inch; and a soil with a lot of clay will require about 1 inch. The two most important points to member are that the required amount of water will vary somewhat according to soil qualities, and that soils that require less water to achieve this depth also hold less water and, therefore, require more frequent irrigation.
To evaluate the amount of water your system is applying to turf, and to properly adjust the timing on your sprinkler system, do these two things:
Measure the water application rate. Conduct this test when there's no wind. Place at least four or five empty tin cans (shallow ones, such as cat food or tuna cans, work well) at various places in the lawn. Don't place them close to the sprinklers or each other. Turn on the sprinklers for 15 minutes. Using a ruler, measure the amount of water in the cans to the nearest ⅛ inch. The average depth from all the cans is the sprinkler system's application rate.
Determine the watering time. Take the water application rate you recorded earlier and find its location on the “Irrigation run time” table (below). This tells you how long to run your irrigation sprinklers to moisten the soil to a 6- to 9-inch depth. The schedule is listed by soil type. If you can't estimate your soil type, use the “clay and sand” category. For shaded turf areas, irrigate for only half of the time listed. On compacted sites with poor infiltration, run the sprinklers for half the recommended time, stop irrigating for 1 to 2 hours and then run sprinklers for the remaining time.
The table does not tell you how often to irrigate, only how long to irrigate to moisten soil to a proper depth. On a mature lawn, you usually can irrigate efficiently by spacing irrigation intervals every 3 to 5 days. However, this can vary quite a bit depending on the weather and your soil type. During the critical mid-summer period, lawns may require 1.25 to 2.5 inches of water per week in hot, dry regions. Clay soils may be able to hold as much as a week's water from one irrigation (though you may need to divide this into several irrigations to accommodate slow infiltration), but sandy soils may require daily irrigation.
The best time of day to irrigate a lawn is during the early morning hours when less moisture will evaporate. This assures adequate water for the daytime stress periods of high temperatures, sunlight and dry winds. Afternoon watering is less efficient because winds can severely alter sprinkler irrigation patterns, and the afternoon sun increases evaporation. Late afternoon and night irrigations can promote disease conditions.
Lawn areas that dry out more frequently than others usually have either a coarser or shallower soil underneath. To help save water, you can hand-water these dry spots. Do not increase sprinkler run times to compensate for a few dry spots, as this will result in overwatering the majority of turf.
If soil salinity is a problem, occasionally run the system longer than usual to help leach harmful salts from the soil.
DROUGHT SURVIVAL STRATEGY
An automatic sprinkler system can save a lawn during a drought. You can program a properly designed and installed system to make the most of available water — something you should offer to your customers. Here are some tips for helping your customers' lawns through a summer drought — and some excellent add-on services to sell!
Irrigate for shorter periods (up to 10 minutes each) several times just before sunrise when evaporation is minimized. Avoid irrigating in mid afternoon or windy conditions.
Raise your mower's cutting height and cut less frequently.
Reseed with turfgrass varieties that are both drought-resistant and water-thrifty.
Aerate your lawn once or twice annually and fertilize moderately. Aeration alleviates soil compaction, permitting the soil to absorb water more easily. This encourages root growth.
Repair irrigation system leaks as soon as you find them. Regularly inspect the lines. Replace worn sprinkler heads and valves as needed.
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