Hi Odin-
Thanks. It's been a long journey to get here, and it continues... I have the small quarter-inch soaker dripline hose you can buy at the H.D./Lowes/the web, embedded in circles around the base of the trees in the RootMaker containers. I'd estimate each sees around 5-8' of hose, and there is a 0.5 GPH dripper every foot along the hose. Right now, I have them set to water with my drip system for all the other backyard plants (but not the main garden and several other trees I have) 3-4 times a day. I was doing a 4-min dwell, but I recently turned it up to 8-min with the crazy heat we're getting here. I am probably over-watering, but I saw some droopy leaves in the midday a while back when it was only in the mid 80's, so I decided better to waste some water than have the trees drop too much fruit just for lack of water.
Also, my soil mixture is very well draining. In fact, I'm in the tedious process of expanding the RootMaker RootBuilder 2 containers for the first time. I'm learning about a few things that I overlooked that I will show with some pics later. The soil mix I'm using right now is roughly 1/3 Peat (and/or Coco coir fibers), 1/3 decomposed granite, and 1/3 a mix of this and that including things like aged chicken manure from my birds, worm castings from my worms (and some purchased), pathbark fines, and various amendments like humic acid, gypsum, mycos, etc.
A lot of the roots for the trees are escaping the RootMaker containers at the bottom periphery of the container where I mistakenly allowed mulch (the black wood chips) to abut and build-up . This gave the roots, over time, and escape route through the first one, two, and a few cases three RootMaker air-holes. Once the roots had a way out, and with all the water run-off, they took off and spread flat along the available space below the mulch and above the weed guard layer I ran to block the ground below. This means that when I walk on that mulch, I likely damage the roots. It also makes it damn near impossible to actually expand the container, but I've developed a painful work-around. I'll describe that in a follow-up post along with some pics.