Respond to climate conditions and plant stress to determine exact watering needs, understanding that sprinklers are to be a supplementary source only. During periods of heavy rainfall, automatic sprinkler systems should be turned off temporarily. Wind is a factor also and watering should be avoided during high winds approaching 20mph. Be diligent in monitoring the weather, choosing when to water makes all the difference. Over-watering leads to weed problems and a shallow root system, while under-watering stresses the turfgrass and promotes an underdeveloped canopy. See the recommended watering guide below to help water correctly throughout the year.

Calibration model: Rotating sprinklers 20 to 40 minutes = approx. ¼” of water. Reduce minutes by half when using stationary sprinklers for equivalent output. Use a rain gauge to confirm exact amount. Watering start times should be from 2am to 6am, zones concluding by 9am or earlier.
Examples below: when watering needs are justified, and no rainfall is present or forecasted.
SPRING 70°~80° (March ~ May) 1/4" of water/wk, one water session/wk
Example all turfgrasses w/rotating sprinkler heads: à 40min/zone x 1/wk @ 6am = ~1/4"/wk
(March & April delay start times until temperatures are above 40°)

EARLY SUMMER 85°~95° (June ~ July) 1/2" of water/wk divided into 2 or 3 watering sessions/wk.
Example warm-season grasses (Bermuda/Zoysia) w/rotating heads: à 40min x 2/wk @ 5am = ~1/2”/wk
Example cool-season grasses (Fescue in sun) w/rotating heads: à 22min x 3/wk @ 5am = ~1/2”/wk 
Example cool-season grasses (Fescue in shade) w/rotating heads: à 35min x 2/wk @ 7am = ~1/2”/wk 
(disease warning for Fescue grass – apply fungicide May 1st)

LATE SUMMER 96°> (July ~ Aug) 1-1/8” (1.125”) of water divided into multiple watering sessions/wk.
Example warm-season (Bermuda/Zoysia turf) w/rotating heads: à 60min x 3/wk @ 5am = ~1.12”/wk
Example cool-season (all Fescue turf) w/rotating heads: à 12min x 2/dy @ 6am & 3pm = ~1.12”/wk

FALL 70°~95° (Sept ~ Oct) 1/2" of water/wk divided into 2 watering sessions/wk.
Example all turfgrasses w/rotating sprinkler heads: à 40min/zone x 2/wk @ 6am = ~1/2"/wk
 Fescue: (if seeded)       12min x 2/day @ 6am & 3pm  first 10 days after seeding (seed ~Sept 1st)
(w/rotating sprinkler heads)    20min x 1/day @ 7am next 10 days
                                          35min e/o day @7am next 10 days
                                          40min x 2/wk @ 7am = ~1/2"/wk - throughout Oct until the end of the season

November – Sprinkler systems OFF and drained to prevent freezing pipes or winter-proof sprinkler system to allow for winter watering if needed.

Hope this helps - Good luck,

- John Mitchell
President/ CEO
GreenMaster Landscape Contractors Inc.
(AKA) Stillwater Sprinkler Co.

(405) 707-0151