How to configure plants in containers?

I have around 70 plants in 1-5 gal pots with an emitter, typically 1 gph. I am in Phoenix, Arizona, so the hot season is coming. How should my settings reflect the container environment? They don’t seem to fit a Shrub profile since their roots will not be that long, have only have a few inches of dirt, and should be susceptible to faster drying out.

I would think these plants would lose water faster than normal, so maybe the Crop Coefficient should go up some amount?

Most of these are shrubs, but the 15 inch root depth would seem wrong. Seems like a lot of the water needs and nozzle calculations would be wrong.

Assuming you are using a drip system, I would set it using a flex daily schedule. Depending on the water needs of the plant and the size of the pot, set it and watch it and adjust the irrigation watering time so that the soil is between 50 % saturated and 100% saturated every other day. You should use drip emitters that emit water faster on the larger pots and on the plants that need more water. Start with the slowest emitter GPH. Slower irrigation will be much better in this situation. Make sure the irrigation emitter is not next to the pot edge or the water will just run down the pot sides and not irrigate the plant.
Do not put it next to the stem or the plant will rot. Put it half way between the stem and the outside edge. If you are daisy-chaining the emitters, make sure that the last pot is getting enough water. If not, there is a pressure problem or a leak somewhere. This is a tweaking process that is required with most irrigation installations.

The soil must dry out between irrigation to allow the air to fill the pore spaces. The pot will feel light when dry. Watch the leaves for changes due to heat, wind or drought. Check it again when it gets hot. You may have to make an adjustment. Once you get it tweaked/dialed in, the controller will do the rest of the work.

I apologize, I am unclear what you mean by “set it and watch it and adjust the irrigation watering time so that the soil is between 50 % saturated and 100% saturated every other day”.

  • "set it and watch it ". Set and watch what? Watch the Moisture Graph? You indicate to “adjust the irrigation watering time” - that is not a parameter I can set. The Flex scheduling determines the irrigation time, although I can calculate the expected watering time based on all the other parameters.

  • “so that the soil is between 50 % saturated and 100% saturated every other day.”. Isn’t this always true? This means the Moisture Graph would be between 0 and 100%, right?

  • If I read this right, you would expect to achieve a 0->100% transition in the Moisture Graph when it is watered (Monday), then it reaches 50% Tuesday, and hits 0% Wednesday so it waters again. Is that right? Why every two days - is there data indicating that a container dries out in 2 days? Or is this based on your personal experience? The container should be dry to the touch when sticking a finger in a couple of inches?

Are you using a Xeriscape, Shrub, or Perennial zone? Are you adjusting the root depth? The Nozzle rate? I currently have a spreadsheet that combines a couple of spreadsheets already out there, so I can adjust the hell out of my zone settings. However, I don’t know what I am shooting for.

I read that to mean Watch your plants to make sure they’re happy. Same for the next point: make sure their roots Have a chance to get some oxygen. Is important to watch your plants when starting any new irrigation schedule to make sure they’re empirically happy & your assumptions are or are not correct.