5 Tips For Planning A Drip Irrigation System

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By supplying regular and targeted moisture, drip irrigation can increase crop production by more than 30% while using 30 to 50% less water than a sprinkler. It also can prevent defects in fruits and vegetables while saving you time.

Click for a diagram of a drip irrigation system.

Bob Schultheis, a University of Missouri Extension agricultural engineer, shares his top five considerations for planning a drip irrigation system for large gardens or small market-grower operations.

1. Determine the quality of your water source for your drip irrigation. Factors may include such things as a pond water source that will require installation of a filtering system or an adjustment of the water pH, depending on your crops.
2. Familiarize yourself with the elevation of the plot/field you plan to irrigate, as it will determine how you size the system and adjust water flow. A 2.3-foot change in elevation, for instance, results in a gain of 1 pound of water pressure going downhill, or loss of 1 pound of pressure going uphill, requiring pressure compensation within the system on steep slopes. Topography, water flow rate and distance also will affect the size of pipes you’ll need.
3. Will you automate your drip system? Depending on the complexity and size of the system, you may need to split watering times between different zones to water spaces incrementally, based on the output of your pump or the water needs of different crops. Automation ensures consistency in soil moisture and in flow, versus turning the water on and off at irregular intervals. The latter is important if you use the drip system to fertilize.
4. Think ahead. As plants mature, they require more water, which is especially important if you are irrigating perennial fruit crops. Build the system with the capacity to supply the optimum amount of water plants will need at maturity. If your irrigation water comes from the same well your home uses, the pressure tank may need to be upsized to reduce pump cycling and possible pump burnout. Or, you can irrigate at night when family water use is minimal.
5. Allow for expansion when installing your system. For systems one-half acre or larger, scaling for expansion up front will save money, as permanently installed pipes should be buried below the frost line and the cost of trenching in pipelines is costly. Size your pipes to accommodate future growth of your operation. Doubling the pipe diameter will quadruple the potential water flow rate.

Drip irrigation is not a set-and-forget-it solution. Systems need to be checked daily as emitters may plug and rodents may cause damage. The system also must be drained to winterize it.

Schultheis recommends discussing your system needs with a university Extension agricultural engineer in your state, or a knowledgeable drip irrigation equipment dealer.