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Can we configure rachio to change the crop coefficient throughout the year to mirror actual crop water requirements?

#1

We have a tall fescue variant that is common in socal.

According to the UC Davis site below, the crop coefficient for tall fescue should be changed throughout the year in order to mirror actual water requirements.

The difference from the winter to spring and summer is rather dramatic and reflects what i have seen in terms of water needs for fescue in San Diego (in addition to the changes that Rachio already takes into account).

Is there a way to program this into the advanced settings of each zone, or would i need to just change it manually each month?

Thanks!!

https://ucanr.edu/sites/UrbanHort/Water_Use_of_Turfgrass_and_Landscape_Plant_Materials/Turfgrass_Crop_Coefficients_Kc/

I copied the data below that corresponds to tall fescue

Table 1. Crop coefficients (Kc) for cool-season and warm-season turfgrasses in California1.

    Month

Cool-Season2

   January

0.61

  February

   0.64

    March

   0.75

     April

   1.04

      May

   0.95

     June

   0.88

      July

   0.94

    August

   0.86

 September

   0.74

   October

   0.75

 November

   0.69

 December

   0.60

Annual Average

   0.80
#2

+1 for this.

#3

Just to provide a little more detail

I have been using flex daily for the past few years. I have dialed in the advanced settings to provide the appropriate amount and frequency of water on “average” with recommendations previously provided here.

I have a Davis personal weather station on site that is linked to rachio to provide the most accurate data possible.

The soil is the concerned zones a thin 4-6" layer of loam overlying typical San Diego dense pebbly clay (redding cobbly loam from the soil series)

However, the grass is seemingly always overwatered to runoff in the late fall/winter (without manual intervention) and develops signs of stress from underwatering early each summer.

From the data I linked previously, warm season grasses in California maintain a relatively constant crop coefficient. However, cool season grasses have a crop coefficient that varies significantly throughout the year.

Especially for species of grass or other plants where more detail is available, it seems that it would be ideal to be able to vary the coefficient to reflect the known behavior of the plant at different times of the year.

With a difference of 0.60 in December to 1.04 in April, the actual crop coefficient shows a peak variation of 73% for fescue grass.

When combined with the evapotranspiration data calculated, it would seem that we would end up with a more accurate watering schedule?

Or is this something that is already being calculated and applied?

Thanks!

#4

We did this in the past, and I’m pushing for this for a future flex daily modification.

:cheers:

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