# New rachio 3 irrigates daily



## Bladerunner (Jun 23, 2019)

Just installed a rachio 3, it irrigates pretty much daily on the flex daily schedule. I know that it wants to "fill the sponge" at first, but it keeps going daily.

This seems to be because my field capacity is only 3.5 mm (0.17in) due to loamy sand soil type (based on my mason jar test, planning for proper soil next in the spring). So the waterings are short and frequent. This fits with my personal experience of the lawn drying out rapidly.

FYI, I have been as accurate as I can with the rest of the setup, with a good local weather station, (better that the weather intelligence setting for me); an irrigation audit; root depth measurement, etc.

I was always trying for infrequent deep watering, but my lawn burned out if not watered for a day or two. I just figured it was the PRG. Now I think it's that plus the sandy soil.

Anyone else have this experience?


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## g-man (Jun 15, 2017)

I think your settings might not be right. You capacity should be 0.17in per inch of root depth. With 4in roots, that should be 0.68in capacity.


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## Bladerunner (Jun 23, 2019)

Thanks for responding, @g-man. Here are my settings:

area: 46.45 cq meters
available water: 0.07 mm/mm
root depth 10 cm (about 4 in)
allowed depletion 50%
Efficiency 80%
Crop coefficient 80%
Nozzle cm/hr 0.45 cm (I have had to manually adjust to fit irrigation audit)

Zone type: cool season grass
Rotor head
Soil type: Loamy Sand
Exposure: some shade
Slope moderate

Moisture balance maxes at 0.38 cm, (110%) (ie, .35 cm max)
Typical ETo is 0.3 to 0.4. I have verified accuracy with your spreadsheet, @@g-man


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## Bladerunner (Jun 23, 2019)

I should add that I played with the soil type and got much greater field capacities. If this is accurate, my loamy sand holds very little water. When they dug out the pool, the "soil" looked like beach sand all the way down to the bottom, by the way.


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## Bladerunner (Jun 23, 2019)

This is from rainmachine site:

Loamy Sand: This soil type is normally made up of sand mixed with a majority of silt and clay. Many people prefer loamy sand soil for their gardening because this type of soil normally allows for good drainage. (Field Capacity: 0.35 in)


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## Bladerunner (Jun 23, 2019)

Ah crap, as I reread that post I realized that I got messed up with the metric conversion: rachio is reporting in inches, not cm, even though my settings are for metric. it is using 0.38 INCHES not 0.38 CM for the field capacity. Thanks @g-man.


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## Bladerunner (Jun 23, 2019)

Nope my mistake, I see that my field capacity is listed as 0.38 CM. I think it must be a software error. I will switch to US to see what happens.


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## Bladerunner (Jun 23, 2019)

Switched to US units, reports max capacity (ie, field capacity) at 0.15 inches. Hmmm


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## Bladerunner (Jun 23, 2019)

I have now posted over on the rachio forum. Will post answer when I figure it out in case anyone else has this issue.


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## g-man (Jun 15, 2017)

Is your ET0 in cm or in? Now I'm confused with units too.

One thing to try is to increase your root depth. This will force longer durations but less frequent (due to a higher field capacity). Adjust and see if it stresses the lawn a bit before irrigation. Ideally you want to push/promote deeper roots.


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## Bladerunner (Jun 23, 2019)

OK I think I am up to speed now.

On the soil moisture page, the view/graph is a bit confusing. Bottom line is, that whole page shows (in my case) only the TOP HALF of the "sponge", ie field capacity, since I have allowed 50% depletion (ie, half of the field capacity).

My field capacity is defined as root depth multiplied by available water for my soil type, ie, 4 in root depth X 0.07 in/in available water = .28 in (0.71 cm) field capacity, not 0.35 cm field capacity. Thanks for your earlier calculation. (If I allow 100% depletion, this whole page works within all 100% of the field capacity. This page causes a lot of confusion, I believe, on the forums!)

As you suggested, increasing root depth will decrease the watering frequency, by increasing the field capacity.

Your calculation was helpful @@g-man, thanks for helping me to figure it out.


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