Sprinklers, Irrigation Systems and Installation

by Ruth Foster

Have you had it hauling hoses around to cope with drought?  Maybe you think it's time for a sprinkler system, especially for your precious green lawn.  If you have some cash to spare it may not be such a bad idea.

However, be forewarned.  Sprinklers are not simple and if poorly designed or badly installed, they will become a permanent maintenance pain.  The two basic types are surface drip systems or underground systems. 

SURFACE DRIP SYSTEMS are the cheapest and easiest to install. They're most useful for shrub beds, vegetables, or flower borders and may also be connected to big planters.

The easiest is 'Leaky Hose' which is just that, a hose that leaks all along its length.  You turn it on and when you think it's enough, you turn it off.  Problems are that it's hard to calibrate, it becomes brittle after cold weather and sometimes clogs with fungus.

More sophisticated drip systems use sturdy plastic tubing to which thin tubes and emitters are attached by punching holes in the plastic tubing.  The emitters are sized according to the size of the plant or shrub and its water need.  A small plant may have one emitter, a tree may have several. Unneeded holes may be closed and new emitters may be added. 

Large systems are often individually designed by the irrigation company which supplies the parts.  These include the tubing, emitters, a line water pressure adjuster, an automatic timer, connectors and T-joints.   

Drip systems deliver water directly to the soil around each plant and therefore use water more efficiently than overhead sprays which lose water to evaporation, especially in dry climates.  And water can be very expensive. 

Surface drip systems are most useful in southern climates that don't have frosts (which may burst the tubing), and they're shorter lived than underground installations.  Breaks in the tubing have to be mended as needed, and in cold climates, the systems have to be blown out with compressed air before winter.

UNDERGROUND SPRINKLERS are what most people are familiar with, especially for the lawn.  They’re usually installed by sprinkler companies. In addition to the reputation and experience of the company, there are some additional things to check out before you sign a contract. 

Most important is the design.   It involves an analysis of your water pressure, choosing the right  components, keeping beds and lawn zones separate, and providing zone-to-zone coverage but without wasting water.  Experienced installers can do it quickly, but be sure to ask a lot of questions.

Check the quality of the parts.  Most contractors don't use only one supplier, but might buy the controller from Rainbird, the pop-up heads from Hunter and the valves from Weathermatic.  How long is the guarantee period?  Winters can be hard on sprinklers. 

Ask about the controller.  Prices range from $80 to $400 and you get what you pay for.  A good one should be able to set different zones for different schedules per week.  There must be manual override so you can

turn parts off and on when you wish.  There should also be a rain sensor to conserve water and not irrigate when the ground is wet. 

If you know plumbing and are handy, you can buy homeowner do-it-yourself kits.  However designing it is complicated, the parts are stiff and tricky to put together plus there's a lot of digging involved, but you can save 50% of the cost.  

The biggest problem is if they are not installed deep enough, especially the do-it-yourself systems.  If too shallow they can be punctured with an edger or lawn aerator.  Frost heaves can push pipes to the surface which may trip someone or be damaged by the lawn mower.  Six inches deep is a minimum, eight is better.   Most systems need professional maintenance in fall and spring, and in northern climates they have to be blown out before frost.

A serious mistake is to adopt a watering schedule for golf putting greens in Arizona (a little each morning).  Such short, frequent watering encourages shallow rooting, disease and lower resistance to drought and heat.  Instead, water less often, once or twice a week, and wet the soil 6 or 8 inches deep,  especially for northern lawns and newly planted trees and shrubs.