A 2- to 4-gallon-per-hour mister sprays the soil and the foliage. Bonsai wire keeps mister head pointing in the right direction.
Thomas J. Story
How many emitters?
All containers running off the same valve will be watered for the same amount of time, but they may not need the same amount of water. To compensate, set up the system for the smaller pots, then put extra emitters in larger ones.
Use one 1/2-gallon-per-hour (gph) emitter for a pot up to 10 inches wide and two 1/2-gph emitters on a T fitting for medium-size pots up to 15 inches wide. For larger containers, make a ring of emitters - four 1/2-gph for a 16-inch-wide pot, more emitters and a bigger circle as pot size increases. Or use 1/4-inch emitter line with factory-installed emitters at 6-inch intervals. An emitter line can also be used in a straight line to water a rectangular container or a window box. For some pots, you may want a specialty emitter such as a mister or a bubbler.
How long do you run the system?
Test your system by running it for 5 to 10 minutes. After watering, the soil should be thoroughly wet, with some water draining out of the container bottoms. If water floods out, you have run it too long; if no water comes out and the soil isn't thoroughly moist, you need to run the system longer or change to larger emitters. Most controllers allow you to run the system several times a day, which is particularly useful in hot climates.