Drip that Fits

Drip irrigation has always been considered an efficient method of watering a landscape; efficient meaning a uniform amount of water applied over a uniform area. But drip irrigation can also be effective by targeting a certain area of the landscape with minimal water to produce a desired effect. To do so requires proper design and proper scheduling.

For proper design, we can use either point source drip irrigation or in-line tubing. However, for the latter we have very specific rules to follow in order to maximize the effectiveness — not the efficiency — of drip.

Point source drip irrigation is an older, but a useful model of drip irrigation. A plastic tube (or tubes) is laid on the ground near the targeted plant and small “spaghetti” tubes are inserted into the tube and placed near the plant.

The issues with point source have always been maintenance of the tubes, brevity of usefulness for perennial plants and the inappropriateness for mass plantings. However, we also stress proper scheduling. Point source emitters are generally in ½, 1 and 2 gallon per hour rates. An established plant never needs more than a ½ gallon of water per week.

What I’m referring to as designer drip follows a rigorous set of design and scheduling rules. If you follow these rules – and contact us prior to any work being done – we might have a rebate in your future. See our website for further details.

Basically the rules for designer drip are as follows: If your bed has six or fewer plants per 100 square feet (4 feet x 4 feet spacing), you must use point source. If your bed has seven or more plants per 100 square feet, you can choose either point source or in-line tubes. But if you choose in-line tubes, you must follow these rules:

  • Emitter rate must be .6 gallons per hour
  • Spacing between emitters on the tube must be 18 inches or more
  • Spacing between tubes must be 18 inches or more
  • A plant must be no more than 2 ½ feet (30 inches) away to be watered by an emitter tube.
  • The tubes must remain uncovered until SAWS inspects the layout.
  • The irrigation schedule must be no more than 6o minutes (1/2 inch) per week or 100 minutes (3/4 inch) every other week.

The fundamental purpose of drip irrigation is to provide plants with water that is slow, infrequent and deep. Multiple times a week watering is inefficient, ineffective and inappropriate for plants. Use drip irrigation for maximum effectiveness and water conservation.

Picture of Mark Peterson
Mark Peterson
Mark A. Peterson was a conservation project coordinator for San Antonio Water System before retiring. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you're likely to find him hiking San Antonio's wilderness parks or expounding on the virtues of geography and history to his friends.
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