Field notes
How long should each zone run in Collin County clay? (Cycle and soak)
Clay takes water slowly, so one long run mostly ends up in the street. Split each zone into two or three short cycles about an hour apart. It soaks in, and it keeps you clear of runoff violations.
Collin County sits on Blackland Prairie clay. The North Texas Municipal Water District puts its intake rate at about a tenth of an inch of water per hour, much slower than most spray heads apply it. Run a spray zone for 20 minutes straight and most of the last 10 minutes runs off into the gutter.
The fix is cycle and soak: split each zone’s run time into two or three short cycles, about an hour apart, on the same watering day. Most modern controllers can do this with multiple start times.
As a starting point in summer, spray zones often need about 6 to 8 minutes per cycle and rotor zones about 15 to 20. The right number depends on the heads, the slope, and the sun, which is why we check each zone on a care plan visit and adjust the controller for the season.