Controllers

A controller directs and controls the watering times applied to the plants. Each valve controls a group of sprinklers called a watering station. "Zone" is a term used to define a group of heads that will be connected to one valve, so "zone" and "station" are often interchangeable terms.

One station will usually correspond to one valve. However, with larger projects, a station can control two or more valves. You can wire more than one valve to a single station at the controller, and all those valves will operate at the same time. Obviously, your mainline needs to be sized to allow this additional flow. You also need to verify that the controller has a transformer size that can operate the number of valves you wish. Some controllers can operate up to two to five valves on one station.

You can also have one valve per station and simply operate more than one station at a time, which is controlled by the “program.”

Controllers tend to have up to 12, 24, 36, 42, or even 48 stations for conventional wiring. These stations are often in modules, so you can pick the number of stations you want the controller to have. Two wire systems can have up to 200 stations or more, depending on the brand. It's cheaper to wire controllers of 32 stations or less with conventional wiring. Controllers with more than 32 stations are cheaper with a two-wire system.

Recommendations

We recommend that you cycle the water, let the area soak in the water you applied, then cycle again, rather than applying a large amount of water at one time. As your site will likely include different types of plants (shrubs and turf, for example), you will need different programs for watering the different types of plants, on different days, etc. Thus, you will need a controller with multiple programs.

You would typically select a controller that has enough stations for your number of valves, and with the level of programs that you will need for your different plant types.

For best results, begin the watering schedule a few hours before sunrise. You'll achieve optimum watering pressure while avoiding wind and allowing the morning sun to reduce mildew. Avoid watering in midday because of wind and quick evaporation, or the evening because of long night hours resulting in mildew.