Irrigation - Water requirements can vary based on a number of factors. Getting the water dialed-in will be the most important maintenance task.

  • Most lawns in the Willamette valley will require between 0’ and 3/4 inches of supplemental irrigation in the spring, and between 1’ to 1.5’ inches per week in the summer.

  • For best efficiency do not exceed .20 inches per irrigation cycle. (Recent studies have shown deep and infrequent watering to be slightly less effective and more wasteful)

  • Determine how long it takes your sprinkler system to deliver .20 inches of water then simply add or reduce the number of water cycles to meet seasonal water requirements.

Irrigation audit.

Any reputable irrigation contractor can perform this service for you, or you can follow along below. The same principles will apply whether you use an in-ground sprinkler, hose end sprinkler. This will tell you how much water (inches per minute) your sprinkler system delivers.

  1. Set up catch basins around the lawn. Empty plastic shoeboxes or coffee mugs work well. Remember the width at the top of the container must be the same as bottom for an accurate measurement. If you have multiple nozzle/ sprinkler types, it will be important to repeat the process in each zone.

  2. Run your sprinkler system for 20 minutes.

  3. Measure the water from each container. Add the total water from each container and divide by the number of containers. This will give you an average. Take this figure and multiply by 3. This will give you your total inches of irrigation per hour. Next divide this number by 60 to give you inches of irrigation per minute. Write this number down for future reference.

    example: .12+.13+.12=0.37, .37/3=0.123 inches per 20 minutes. .123X3=0.492 inches per hour. .492 inches/60 =0.0082 inches per min.

Programing the sprinkler

  • For those using an electronic timer, set each zone to irrigate .20 inch. To determine how long this will take divide .20 by the “inches per minute” figure you calculated.

    Using our previous example we would set the timer for 24 minutes to deliver .20 inches of water.

    Example: .20/.0082=24.39

  • Start with 4 watering cycles per week spaced evenly. (M.,W.,F., Sa. or e.o.d.)

    In our example you will set each day to run 24 mins, giving you .20 inches per cycle for a total of .8 inch per week.

    Seasonal adjustment

    If conditions warrant, add or remove watering cycles to meet seasonal requirements. Avoid increasing the watering duration per cycle but rather increase total weekly time. The term “Cycle” is referring to an individual irrigation event.

  • May-june - 0-.75 inches per week - (1-3 cycles per week)

  • July-aug - 1-1.5 inches per week - (4-7 cycles per week)

    Fine tuning

    As you become more familiar with your individual lawn, you may need to make some fine adjustments. For example…

  • You may notice a a shaded area is getting soggy and needs less water. Make incremental reduction.

  • If a lawn area exists on a steep grade, it can often be helpful to increase the watering frequency, while keeping the total weekly volume the same as before. This can improve efficiency by helping to prevent run-off. If this doesn’t resolve the issue, we recommend the use of a wetting agent.

    example: 24 min cycle x 4 days=96 mins per week. 96/7 days=14 mins per cycle