oh crikey.. an engineer... lol ..

watering is an art.. not a science... you tend toward scientist ... and it is warping your head.. isnt it.. lol ...

you have tried to figure out your soil.. and how water works in it ... fantastic...

based on said knowledge.. you have to GUESS .. what is best ... no one can really tell you otherwise ... since we cant guess as to your soil ...

just do the best you can ... and wing it .. words that make a real engineer pale... lol

and do note.. ALL my best friends are engineers.... so this is all tongue in cheek... but rooted in knowing the psyche of the profession ...

in all those words.. i dont know how long you will be gone ... a transitory watering issue is not going to kill a plant inside a month or so ... so on some level.. i think you are over-worrying ...

and lets be very clear ... YOU PLANTED 45 .... you most likely will have a loss or two ... and until that time ... you will not know your success ... heck.. with all my experience.. i would expect a failure rate ... so dont flip out and try to figure out why.. the exposure starts with not knowing how successful the dig was at inception of BB ...

prepare for some loss.. and learn a happy dance.. if you win ...

i dont know about your little water wand... but its better than not having any knowledge ... and you should also be inserting your finger.. under the mulch.. to teach it how to do it ... the meters eventually fail ...

and finally ... i wish you would have.. wait for it.. gone with an engineered water delivery product ... crikey.. the one place you could have had the science.. instead of the art ... you went art ... little brain freeze there??? ... it would not have been a significant cost difference ....

with said product.. your failure will be at distance from the spigot ... as pressure is not maintained thru the whole run... when i used such.. i would swamp the first plants.. trying to water the last plants...

so put all your focus in the end of the run ...

presuming you arent leaving for months on end.. i would tend.. now that the heat of summer is starting.. to err towards extra water... this is the key season to INSURE the root masses do not dry out ... and then when fall hits.. we can dry them out... for winter.. if need be ...

you are not going to kill the batch... but for the worst clay soil ever .... and i dont think you have that ...

you have analyzed.. and considered every variable know to the gardening world.. i hate to tell you.. you are now left to the whim of mother nature .... with decades of messing with her.. let me sum it up with.. GOOD LUCK WITH THAT ...

i hope this was helpful.. and that you have some sense of humor ...

i wish you luck ...

ken

ps: if you have failures.... talk to us then ... but in case i forget this brainstorm ... you can re-harvest some of what you have.. and place them to fill a hole .... and then plant some diverse plants where you take stock from .... lets not talk about failure right now.. but if so.. remind me about this ....

Many, many thanks for this advice. You are right, I should have gone with a better drip irrigation system and I still might do that. I was thinking the soaker hoses would be good enough, but I think I'm more comfortable using them on perennials than trees. I underestimated the level of concern I'd have for "things I planted with a skid steer" versus "things I planted with a shovel". Perennials seem almost disposable in comparison.

Thanks for the humor, I was so tempted to put in a data acquisition system to monitor soil moisture at each tree but talked myself out of it (for now, at least). Next year, after I've gotten these guys partly established, I want to add some more evergreens to the bed for more interest. But definitely smaller (lighter weight!) things - I was surprised how much these things weighed, which is good because if I'd known that I wouldn't have done the project ;)