I will be going on vacation for two weeks and I don't trust any of my neighbors to water my container trees in my absence. I've currently got them on timers but they still require a lot of oversight because of the differing needs of the plants served. I know I will need to make some concessions and I'm hoping for some feedback or ideas as I try to get this setup in a way that will keep all my trees alive for two weeks....
I have two lines on two different timers. On one line I have a propagation tray with sour orange seedlings. This is set to run daily for 5 minutes.
On my other line, I have a bonanza peach, Meyer lemon, meiwa kumquat, and ruby red grapefruit, all in 7-10g size pots, in 5-3-2 (pine bark/perlite/peat) mix. This runs every other day for 30 minutes and emits a little over 7 gallons per container. The peach tree has a much larger rootball:container ratio and is the reason this timer runs every other day. I switch the supply valve for the other trees after every other watering so they only get watered every 4 days. I obviously can't switch the individual valves if I'm on vacation, and I believe I will get leaf drop if I let the citrus get watered every other day. Despite the heat and the fast draining mix, that's what happened everytime I've tried to water them every other day.
What I would like to do is put all my citrus trees on one timer that runs every 3 days. 3 days is too long an interval for the peach tree, so I thought about moving that to the daily timer with the seedlings. I'm not worried about watering the peach tree too frequently, it uses the water much faster because of its larger rootball, and it seems less sensitive to wet feet than my citrus. However, the seedling timer it would share only runs for 5 minutes. This would give the peach tree 1 gallon every day, instead of 7 gallons every other day. I could up the time but the propagation tray cells are small and that would waste a lot of water.
It's going to be 110+ F and the trees are shaded in the afternoon. You would think such extreme heat would make overwatering a non-issue, but I believe it becomes an even greater risk because the roots slow down when they get hot, making them more vulnerable to watering issues.
Given the differing watering needs (small propagation cells need daily short waterings, peach tree needing at least e/o day, and citrus trees needing about every 3-4 days) and resources available (2 lines with 2 timers), how would you put it together? I should add the trees have emitters dispersed for about 14gph.