Water Recommendations for Vegetables Sheriden Hansen, Utah State University Extension Assistant Professor, Horticulture Taun Beddes, Utah State University Associate Professor, Horticulture Burdette Barker, Utah State University Assistant Professor, Extension Irrigation Specialist Ashley Butler, Agriculture and Natural Resources Department Program and Communications Coordinator
Irrigation in the Vegetable Garden In Utah, water is continuously in short supply due to population growth, a warming regional climate, and continued drought. With this, demand for water has increased while becoming less available. As far as water conservation, an area often overlooked is the vegetable garden. Traditionally, we irrigate using overhead sprinklers and/or flood irrigation. However, these methods can be wasteful, and so a way to conserve and still have a healthy garden is to use drip irrigation. It can reduce water use by up to about 50%.
There are two general drip emitter types: point source and inline. Point source emitters are individually placed at the base of a plant to maximize water efficiency by only irrigating individual plants. Inline emitters are spaced evenly along a pipe or hose so there is an emitter every 6 or 12 inches, for example, and are often laid in a grid pattern. Both drip tape (temporary) and drip line (more durable and permanent) are examples of inline emitters.
When using drip, it is hard to know how many inches of water are delivered every hour with emitter flow rates listed in gallons per hour. Vegetable garden irrigation recommendations are usually listed in inches of water per week and needs will vary based on growth stage, soil type, and temperature. Tables 1 and 2 include lists of the time needed to apply a ½ inch of water of both drip tape and drip line capacities, respectively. These tables include rates and spacings of common products that should be easy to find for the home gardener.
Table 1. Drip Tape Application Rate and Time Needed to Apply 1/2-Inch Water to 100-Foot Row, Assuming 2-Foot Row Spacing
Tape diameter
Emitter spacing (in.)
Gal./hour/ 100 ft
Gal./min./ 100 ft
In./hour
Hours to apply ½ in.
5/8 5/8
8 12
20.0 27.0
0.34 0.45
0.16 0.22
3.15 2.30
Note. Calculations are based on tape diameter and emitter spacing. Rates assume irrigation is run at the manufacturer’s recommended PSI.
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