Sprinkler Tune Up Advise
from the Landscape Committee

Sprinkler systems are in constant need of service. Because sprinkler systems consist of moving parts, these sprinkler parts will wear out.

June, July, and August have the highest evapotranspiration rates in Plymouth, and require the most supplemental irrigation. Here is a quick tune-up checklist when doing sprinkler repair. 

1. Make sure your timer is set to the correct time/day. If you experienced a power interruption during the Winter, your sprinkler timer may have returned to the default program which is generally 10 minutes per lawn sprinkler zone, set to run every day. Not only is watering every day bad for your plants, wallet and the planet in general, it also violates watering restrictions in many municipalities. If this has happened to your controller, you need to change the backup battery in the sprinkler controller. Be sure to check if your sprinkler timer requires a rechargeable battery. If it does, and you replace it with a regular battery you can harm the controller circuitry. 
2. Visually inspect each sprinkler zone. Starting with the first zone or section, look for: 
   
   A. Leaking seals on worn out sprinklers. Old leaking sprinklers can not only waste a lot of water and raise your utility bill, they can steal pressure from your zones leading to a lack of proper coverage. 
   
   B. Rotors not turning. Rotors, the heads that move and throw a long distance, will eventually stop turning. Rotor heads need to turn in order to provide head to head coverage. When closed case rotors stop turning, for example Hunter PGPs, they need to be replaced. 
   
   C. Heads too low in the turf. This is one of the most common problems seen grass types that produce thatch. As the thatch layer grows higher it begins to disrupt the spray pattern of the sprinkler head. If the spray head seems significantly low, you can replace it with a taller head. For example you can change a 4” pop up to a 6” pop up. If the head is only slightly lower than it needs to be you can raise it with a “riser extension” which are commonly available in all hardware stores. 
   
   D. Plants blocking spray heads. As the landscape matures, often the sprinkler system needs to change along with it. Using flexible PVC hose or ”funny pipe” you can move the sprinklers in front of the shrubs into the turf. Then you can install adjustable sprinkler nozzles to throw some water back into the shrubs which are now behind the spray heads. Don’t worry if the shrubs do not receive as much water as the turf. Established shrubbery does not require as much water as does turf due to their deep root growth. 
   
   E. Clogged spray nozzles. It takes only a tiny amount of debris to clog a sprinkler nozzle. When that happens coverage suffers. If it appears to only be a slight clog it is often possible to tap on the nozzle with a screw driver handle to clear the obstruction. Some spray heads come with built in nozzles that cannot be replaced such as the Hunter PS. In this case, open the adjustable nozzle all the way to a 360 degree pattern. This will sometimes flush the obstruction. If it does not, the entire spray head must be replaced. 
   
   Misaligned sprinkler heads. Sprinklers get out of adjustment as do most things with moving parts. Make sure that you are only watering the landscape, not the road or your patio. Straighten any sprinkler heads that have tilted and are no longer straight. 
   
   F. Set individual zone run times. There is no “one size fits all” equation for setting zone run times. There are to many variables such as soil conditions, sun or shade areas, and sprinkler system design efficiencies. There are some basics that we can use to determine sprinkler run times. First, rotors and sprays have different run times due to their precipitation rates. In general, rotors must run three times as long as spray heads to deliver the same amount of water over their given area. So if the spray heads run for 7 minutes then the rotors need to run for 20 minutes. However, applying the needed amount of water all at once can lead to other problems. If you have a dense soil the amount of water required by the plants will run off if applied in one application. So rather than apply 12 minutes all at once, it would be more beneficial to apply three separate applications of four minutes each. This is accomplished by setting the controller to three separate starts times spaced closely apart. If you have four zones consisting of two spray and two rotor zones, the settings would be as follows. The spray zones would run for seven minutes and the rotors for twenty minutes. This is a total system run time for all zones of 54 minutes. We can then set the sprinkler controller to start every 60 minutes in succession. We would want the last start time to finish near daybreak so our start times would be 3:00, 4:00 and 5:00 AM. 
   
   G. Adjust your controller at the beginning of each month as follows:

1. April = Run manually as needed.

2. May = One start time every other day.

3. June = Two start times every other day

4. July = Three start times every other day.

5. August = Two start times every other day.

6. September = One start time every other day.

7. October = Run manually as needed.

Hugh Ellis, For Landscape Committee

SOURCE: Email - July 21, 2009