Custom Evapotranspiration Coefficients

Spruce generates recommendations for watering using an evapotranspiration model. The coefficients for this model are generated using common values for the nozzle, soil, and landscape types, which can be set for each zone in the Devices page.

To tune these recommendations for your zones, you may also enter custom evapotranspiration coefficients:

  • Precipitation Rate– the precipitation rate of the watering nozzle as inches per hour
    • lower numbers mean the nozzle dispenses less water, resulting in longer water times
    • higher numbers mean the nozzle dispenses more water, resulting in shorter water times
  • Crop Coefficient– the coefficient for your specific crop or landscape type
    • lower coefficient means the plants require less water per day
    • higher coefficient means the plants require more water per day
  • Allowed Depletion– the moisture depletion inches per day for the zone
    • lower number means the plant roots need to stay wetter
    • higher number means the plant roots need to dry out between water

Note that changing these values will only change the recommended watering values for your zone; if you already have schedules set up, schedule durations will need to be changed manually in the Schedules page.

To edit these values

  1. Go to the devices pageapp.spruceirrigation.com-devices(iPhone 6 Plus) (2)
  2. Select the zone to editDevices-Zone select
  3. Check “Use Custom Evapotranspiration Coefficients”Devices-Zone-Evap
  4. Enter the values you would like to adjustDevices-Zone-Evap_exp
  5. These setting changes will not effect current schedules, you must create a new connected schedule for the modified Evapotranspiration values to take effect.  Go to Connected Schedule for instructions.

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