Application Rates
Watering application rates will vary with different types of
plants, soils and climates. New lawn must be kept moist, and
newly-transplanted shrubs must be watered every day or two.
Established plants will need deeper, less frequent watering. The
following guidelines will get you started.
Watering Guidelines
1. Do not operate more than one valve at a time.
2. Water early in the morning when it is least windy and
pressure is the greatest. Early morning watering will also
reduce water evaporation. Watering in the early evening
is not recommended. A lawn is more likely to get diseases
when wet for a long duration, especially overnight during
the summer. Watering on a hot summer day may also burn
the plants, due to evaporated salt on the leaves.
3. In most areas, lawns require 40 mm to 50 mm of water
per week in the hottest months. Hot and arid areas may
require more.
4. Manually activate your system every week or so to make
sure everything is operating correctly. Check and clean
sprinklers to ensure proper functioning.
Freezing Areas
In freezing climates, turn off the controller, close the main
sprinkler shut-off valve, drain all the water from the system,
and blow any remaining water out of the system before the
first freeze. If you are unfamiliar with the correct procedure for
blowing out a sprinkler system, contact your local Hunter dealer
for assistance or a referral.
Choosing Sprinkler nozzles
When designing an irrigation system, it is important to ensure
that the precipitation (rate at which water is applied) is even over
each zone of coverage. “Matched precipitation” is accomplished
by selecting the appropriate nozzles, or zoning together
sprinklers with the same precipitation rate. The two criteria to
consider are a sprinkler’s flow rate and arc of coverage. The
illustration (below) depicts three different sprinkler heads with
matched precipitation rates. In each case, one gallon per minute
(GPM) is applied to each quarter circle and precipitation is
therefore matched.
Watering Guidelines
WATerinG GUiDelineS
Cool, non-arid climates – Apply 25 mm of water per week.
Hot, arid climates – Apply 50 mm of water per week.
Clay soils, fine particles,
absorbs water slowly
Program the controller with
shorter run times; increase the
number of start time cycles per
day; decrease the number of
water days per week.
Loam soils, medium-sized
particles, average
absorption rate
Program the controller with lon-
ger run times and fewer start time
cycles per week.
Sandy soils, larger particles,
absorbs water quite rapidly
Program the controller with
shorter run times; increase the
number of start time cycles per
day; increase the number of water
days per week.
SPrinkler rUn TiMe SCHeDUle – Over 7 DAyS
Water To
Apply Each
Week
Spray
Sprinklers
PGJ
Rotors
PGP
®
Rotors
I-20 Rotors
25 mm
40 min.
130 min.
150 min.
150 min.
50 mm
80 min.
260 min.
300 min.
300 min.
An automatic controller stores information on what days to
water, what time to start watering and how long each zone
will run.
NOTE: For complete information on products and performance
charts, see the Hunter Product Catalog or visit our web site at
www.hunterindustries.com.
90˚
180˚
360˚
= 5 l/min
= 10 l/min
= 20 l/min
