Why two days in a row?

Hey folks—

I have two particular Flex Daily zones that are confusing me.

I was hoping they would water deeply and run every 10-14 days. So I tweaked the co-efficient until the water depletion calendar showed me the spread I was looking for.

What I’m thrown off by is that these zones will run for say one week between watering, and then literally water again the very next day. And not only that, they are watering for shorter periods of time, but two days in a row, instead of for a long period of time like I anticipated.

Could we see your other settings too, including your Nozzle Flow?

Crop Coefficient is way too high; I assume that’s what you played with. Increasing it will DECREASE the time between watering, and also apply much more water (maybe twice) that which is needed.

You’re putting 2.5" of water on the zone each time. Boy, that’s a lot of water, but it certainly should space out your waterings. Do you have Soak turned on?

It kinda looks like you may have two schedules operating on this zone. Maybe a Fixed schedule plus a Flex Daily? What type of schedule are you using?

I’m using .9 GPH drip line and using cycle and soak because of a bit of a slope and because I have rock hard clay.

I chose “fixed spray head” because Support asked me to after I was having issues with Cycle and Soak not working when using the drip setting. Yes, they asked me to delete all my zones, reboot, restore factory settings, and start from scratch, and it still wouldn’t cycle and soak. So finally they asked me to change the nozzle to spay head.

That said, what is your Nozzle Flow set at. Sound like with 25" deep roots, you have a good size tree (I’ll guess at 6’ canopy), so if you’re only applying 0.9 GPH to a 6’ circle (28 sq ft), that works out to 0.05" per hour. Meaning it would take almost 50 hours to get the 2.5" your above settings dictate.

Obviously, something’s messed up here.

I’m surprised that with only applying 0.9 GPH you need to cycle and soak.

Design looks like this except my mature trees (5-7 feet canopy) have three concentric rings of drip line with 18” spacing between emitters.

Nozzle inches per hour is set at 1.5”. I think that’s the default setting in Rachio for this spray head.

Very nice system for trees. Good for you to do something like that.

Sure, but as you say, you don’t have spray heads. I’m guessing EACH emitter is set for 0.9 GPH? In which case you’d have N times that, where N is the number of emitters for each tree? I doubt very much you have a 0.9 GPH flow control for the entire zone with all the emitters.

IF that is the case, then your Nozzle Inches per Hour would be:

Nozzle Inches per Hour = Total Flow (gal/hr) x 231 (in³/gal) / Area (ft²) /144 (in²/ft²)

         = N x 0.9 GPH x 231 / (Dia² * 3.1416 / 4) /144

         = N x 0.9 GPH / Dia² x 231 / ( 3.1416 / 4) /144

         = N x 0.9 GPH / Dia² x 2.0425 (Final formula for 0.9 GPH emitters)

For 10 emitters and 6’ diameter area that would give:

Nozzle Flow Inches per Hour = N x 0.9 GPH / Dia² x 2.0425 = 10 * 0.9 / 6² x 2.0425 = 0.51"/hr

You should probably use a diameter about 1.5’ larger than the largest ring diameter, due to the spray to the outside.

Oh, and if you have several trees on the same zone, then you’d have to include all the emitters and areas.

Quick question about your formula: How did you get 231 (inches/gallons)?

I have approximately 31 x 0.9 GPH emitters on my largest tree.

(The drip line I’m using is Hunter’s HDL and it’s pressure compensating and I’ve installed it approximately 6” sub-surface. I have found that pressure compensating drip line from brands like Hunter and Netafim are far more reliably uniform in applying water than using individual barber emitters which have all sorts of problems and sometimes get clogged.)

It’s 231 cubic inches per gallon. It’s one of the definitions of a gallon.

Wow. So 31 x 0.9 = 28 GPH or a little less than 0.5 GPM.

I’m sure they’re good, and don’t doubt they work very well. I do question whether a drip line buried 6" into of “rock hard clay” would still produce the rated GPH. Or, that you have to worry about soaking time since the water has to travel upwards through his clay to overflow.

Sorry, I DID complicate the formula more than necessary. What is normally used to measure Nozzle inches per hour when measuring water flow and area is:

Nozzle Inches per Hour = Flow GPM / Area (sq ft) x 96.25

In the example above, I used 10 emitters each with 0.9 GPH so that’s 9 GPH or 0.15 GPM. And the 6’ diameter area would be 6 x 6 x pi / 4 = 28.27 sq ft.

So, the Nozzle Flow would be 0.15 / 28.27 x 96.25 = 0.51" (the same answer). I used the complex version to show where the 96.25 comes from.

Cool! Was just sharing the brand in case you were interested :smiley:

I did condition the clay with gypsum to make it a bit more porous. But yes, anytime you work with clay soils you have to think about water traveling excessively horizontally which is why I selected to Cycle and Soak. I do wish I had purchased 0.6GPH or even 0.4GPH but that ship has sailed.

I want to go back to my original question which was why would Rachio water two days in a row? I set the Watering Duration to 1 hour and 30 minutes. However Rachio will water 1 hour today and 30 minutes tomorrow. What’s up with that?

I can’t answer that. I can say that any time you make changes to a Flex Daily schedule, it seems like Rachio has to adapt to it some how, and it doesn’t do that instantly. Check the graphs for the next two weeks for the zone(s) in question. When does Rachio plan to water (only Flex Daily waterings should be shown). Considering any forecast rain, does the graph look like it should, and water a standard amount when approaching zero moisture, then hold off until it approaches zero again? Can you post the tables below the graphs (they’re more accurate and easier to see than the graphs themselves)?

The graph doesn’t indicate it will water two days in a row but… it will. :thinking:

Please post the More Detail screen as well. It still sounds to me like a separate schedule is watering, while you’re trying to use the Flex Daily schedule.

Nope just a single schedule. It takes the total amount of minutes I want to water for and splits it into two, across two consecutive days.

@DemoDrip , the More Details information that is below the graph is what you need to click on and post to have the community have a better chance of helping you.

I’ve never heard of Rachio splitting times that are entered, except to Cycle & Soak. Are you using manual Cycle & Soak, and if so what are your settings?

Could this be just a reporting artifact if the scheduled watering time crosses midnight?


Wow, @beranes might have just nailed it!? What do you have for a start or end time for the schedule @DemoDrip?

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Man that’s wild.

I have it start after sunset… but the schedule runs multiple zones so…

I’ll report back after the next run.