Depletion value vs full and Dynamic Crop Coefficient questions

How does Rachio know that a zone is full when the system is set up for the first time? From what I read, the % shown on each zone can be as high as 110% but on that scale 0% would actually be at the depletion level set in the app (default of 50). When the zone does show 110%, that part of the yard still seems to be dry.

Please explain how Rachio determines the zone is actually full.

I’m in central Florida. Should I be using dynamic crop coefficient instead of the static? I have St Augustine grass

That all sounds correct. The depletion level is the least water you can tolerate in the whole soil profile. Your root zone(s) are above that level (some call the depletion level the “wilt line”). Soil moisture - the only part you care about - where you grow things - extends from that depletion line (0%) and the top of the profile (100%). My experience is that water applied or estimated to have been applied with irrigation and rain that would over-fill the profile is shown as 110%, and usually results in Rachio not having anything scheduled for a while. When using Flex Daily, Rachio will regularly monitor the use/transpiration/evaporation from the zone until irrigation is needed. With other types of scheduling, there’s far less protection from over or under-watering, which may be why most older controllers (timers) over-water by default, which of course is why you’ve got a Rachio.

I grow St. Augustine in Texas, with a clay loam profile about a foot deep. Rachio waters no more than twice a week, even in heat, and it goes dormant in winter. Some Floridians have a sandy profile 10 feet deep which requires less water more often and it never goes dormant. Soil type, crop coefficient and a good local weather source are important to both of us for different reasons. I’ve never enabled the dynamic crop coefficient. Give it a try and tell us what you find out.

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It is a calculation based on the soil type, and how much water it can hold, then depletes based on ET and other factors.

One of the reasons I’m questioning all of this is because of the soil moisture #'s I’m seeing. One zone ran last night for 1 hr 13 min (normal run time) and this morning the soil moisture was 72%. It didn’t fill it up to the 110%. Another zone ran for 53 min (normal run time) and its soil moisture is 84%. My other 3 yard zones are 102%, 95% and 93%.

I would have expected all to fill up to %110.

FWIW, I’m getting weather data from my personal Davis Vantage Pro 2 station.

It doesn’t necessarily fill to 100% each time it waters. It will make sure that it stays above allowed depletion before the next watering. It depends on the ET calculations for the day, which won’t always be the same.

If you look at the graphs and charts, it might make more sense…