Questions on Bubbler zone


#1

Rachio 3 in Phoenix, AZ

I have only one zone right now and it only waters trees…mostly pretty established.

  • 4 of these trees are ~ 30 - 40ft high
  • 4 of these trees are citrus ~ 20 ft high
  • 2 are new planted ash ~ 7 ft high that took the place of 2 other downed 40ft ers

All of these trees have 1 bubbler at the base of it. Currently the zone is setup as a bubbler.

Questions

  • How do I convert Nozzle Inches per hour into gpm or lpm? It seems that unit of measure should be rate of volume dispensed, not rate of inches…(or if inches, what is the assumption for area to get volume?) Right now I think I have a very similar bubbler to the video so I have left it at 1in/hour.

  • I have heard that the bubbler nozzle type does not support soak. Do you recommend changing this setup to a spray? Again I would be more comfortable if I knew how to convert to gpm. I do see some run off now and the bubblers are only open halfway. I’d like to open them all the way so I know exactly how much they are putting out and then insert that number into the app.

  • Any ideas on what to do for the newly planted trees? I can’t water them like mature trees but I also can’t setup a new zone just for them right now. I’d like to figure this out before the heat sets in.

  • I have set the root depth to 24in and allowable depletion to 50%. That being said, it also tells me that soil moisture is currently 12%? Shouldn’t it have watered before it went below 50%? What the difference between the two metrics, please?

Thank you!


#2

For trees at least, the area to use for getting in/hr the area within the dripline of the tree. So the radius of the circle is the distance from the trunk to the furthers branch tip. Roots will grow at least as far as your dripline. Overtime, of course, this area increases as the tree grows. So you’re right that you can’t water new trees like the old.

The conversion to in/hr and other details of settings up drip (maybe not bubblers) can be found on a spreadsheet at Drip Emitter Calculator for Precipitation Rate & Area

People have used Spray instead and set the appropriate nozzle inches/hr (precipitation rate) to get soak. Bubblers can output a lot of water real fast, so soak might be a good idea if your soil can not accommodate its output over the time of watering, Now if you have water basins around your trees, then so long as they don’t overflow, you won’t need soak.

New tree roots aren’t too deep but you still want to water a bit deeper to encourage deep root growth. So you probably don’t need to water to the full 24”, maybe start at 12” or some depth beyond the pot depth the trees came in. You can increase the depth over time if you feel the tree would be able to reach deeper water. For my orange trees, I’ve set it to 12” permanently since they can get most of the water from the upper soil where the bulk of the roots are (you can do research on root depth, always fun!). Also as mentioned above, the dripline for new trees will not be large so the “area” you water will be less and that affects your precipitation rate (nozzle in/hr) quite a bit. Each year you can measure the new drip line area and adjust your in/hr until the tree is mature or as big as you like (and pruned to keep size/shape).

Most of the time the % number you’re looking at for soil moisture is the soil moisture balance. If depletion is set to 50%, the % balance only looks at the amount that is allowed to deplete. So… its 12% balance of that 50% allowed to deplete.


#3

See also:


#4

There are 3.89 liters to a gallon.

1 cubic inch per hour is equivalent to .0043 gallons per hour.