A hard hose emitter line with a dripper (hole) visible

Drip irrigation should be considered the primary method of providing water to your raised bed garden. It is the only method compatible with plastic mulch culture.

Drip irrigation is defined as the frequent, slow application of water to the soil through mechanical devices called emitters. Operated properly, drip irrigation delivers the ideal amount of water to your crops at the ideal rate, thus avoiding the drench or drought phenomenon associated with other watering methods. Less plant stress translates into optimum growth and greater yields.

Every drip system has three general parts: 1) the head unit, which includes all control components and a filter; 2) a transmission system of plastic hose or pipe; and 3) the emitters. Sources of water to supply the system might include a municipal water supply, well or holding tank.

Components of the head unit include a valve to turn water on and off; an anti-siphon valve designed to prevent contaminated water from flowing back from the system into the domestic clean water supply; a pressure regulation device designed to maintain the optimum working pressure; and a filter to prevent entrance of damaging foreign particles such as sand and silt into the drip system.

Water flows from the head to the emitters through plastic pipe or hose or a combination of both. This main line should be buried to protect it from light and physical damage, and to keep the entire installation less cluttered.

The kind of emitter recommended for use in permanent raised bed gardens is referred to as a line emitter or emitter line. They are ideal for closely spaced crops such as flowers, vegetables and small fruits.

Several types of emitter lines are on the market. Some of the more popular include double-walled polyethylene collapsible tubing, soaker hose and hard hose with pre-installed drippers.

The collapsible tubing is commonly referred to as tape. This type of emitter has openings in the outer wall every 12, 18 or 24 inches.

The soaker hose type of emitter is equipped with very fine pores throughout its length. This type of emitter is commonly manufactured from recycled automobile tires.

We have used both the tape and the soaker hose emitters extensively in our raised bed operations. The soaker hose emitter proved unsatisfactory due to its lack of application uniformity. Tape emitters provide uniform water distribution. However, because of their thin wall design, they are susceptible to rodent and bird damage.