Many gardeners believe that a drip irrigation system consists solely of drip lines with preinstalled emitters at fixed intervals. However, drip systems can have a combination of emitters and other water distribution devices, including sprays and mini-sprinklers.
Drip lines most often have emitters embedded in the wall of the tubing. These factory-installed emitters can be 6, 12, 18, or 24 inches apart. Drip line or hose is also available with no emitters. The user can then install emitters at any desired spacing. The hose can be put in place and emitters installed (with a special punch) to exactly match plant spacing.
A wide range of drip emitters is available to provide the water flow rate needed by the plant. These emitters can be installed directly into the wall of the hose, or a piece of small-diameter tubing ("spaghetti tubing") can be connected to the drip hose and an emitter connected to the other end. This allows the drip hose to run across the center of a bed in a straight or slightly wavy line, with spaghetti tubing running off it to deliver water to perennials or small shrubs in other parts of the bed.
In some situations the gardener wants to water a wider area than a drip emitter would cover. A seed bed, or a plant such as watercress, needs high humidity. In this situation the emitter can be replaced with a spray unit. These are often held in place with a ground stake that can be anywhere from a couple of inches to a foot or more high. Some units have an adjustable spray, while others spray a fixed area.
A higher volume of water can be provided by a mini sprinkler, which like a spray unit can be installed directly into the drip hose or at the end of a spaghetti line connected to the hose. These units can also have a ground stake to lift the sprinkler above foliage or allow it to water a wider area.
Drip, Spray, or Sprinkler?
This decision has to be based on the needs of the plant. As a general rule, it is better to keep foliage dry by using a drip emitter. However, large plants or the need to water a large area can make a spray or sprinkler just what is needed.