No rain, no water? Why?

[rraisley]

@cg2000

Hey Rraisley, your posts are super helpful in helping to decode what on earth the Rachio app is up to! I wondered if you’d be willing to write a brief guide that lists out each variable in the Advanced Setting and what it does if you increase or decrease it?

Thanks. While I was learning, I did write up this topic that might be of help to you:

A Beginners Guide on Understanding and Using ALL THOSE ***** NUMBERS!

Also, a specific question, do you understand what the unit in/in means for Available Water? Is it inches of water per hour per inch of dripline? Cheers!

Available water is the amount of water per unit that a given type of soil can hold. If I’d have invented the term, I’d have simply used Percent as the value (my soil, per a site that lists values based on actual location, is 17%). However, the Industry states it differently: They state the inches of water per inch of soil (yes, that’s the same as just a fraction); in this case my soil would be 0.17 in/in. And if you’re working with metric, to confuse things further, it’s written as 0.17 cm/cm or 0.17 mm/mm. It could have been 0.17 miles/mile!

So, it’s just a fraction/decimal/portion of the soil that is water, based on the soil type. That number times the root depth (D) gives a total inches of water that the top D inches of soil can hold, and if we want it to decrease by 50% before watering, it tells us we can apply AW x D x AD (Available Water x Root Depth x Allowed Depletion) at once, and then wait for it to use that much water before watering again. In my case that’s 0.17 x 6 x 0.50 = 0.51" of water. This calculated number is important because the amount of water applied by Rachio is calculated directly from it, and the length of time Rachio waits to water again is also calculated from it. Sandy soil can’t hold much water, so no sense in overwatering it, so you apply less, but more often.

Hope this helps.