How do you know when to water you mature and not so mature fruit trees...Apples, stone fruit, persimmons, etc

[CRhode]

I replied to a similar topic a couple of years ago:

Watering with 5 gallon buckets

I have 20 trees, and I get by with junk garden hose that I leave in place all season. Here’s a parts list: Vacuum breaker. You need this at the hydrant so that fluid in the hose doesn’t run back out the weep hole there after the hydrant is shut off. This uses hydrant threads female-male. Pressure reducer. You need this at the vacuum breaker to step-down the water pressure at the hydrant to 30psi. This uses hydrant threads female-male. Quick couplers male-female. I use these on eit…

That post includes a reference to irrometers, which are devices for measuring soil moisture. They come in various depths and porosity for various soil types, and they’re calibrated in kilo Pascals (kPa) of vacuum. Of course, this isn’t directly useful as an indicator of plant stress, but, after irrigating, you can note whether the plants respond and begin to correlate in your mind how much difference a watering session makes in the vacuum. Thus, you learn how often to turn on the water, guided by the irrometer reading. The trick is to stay out in front of stress.