Ya I've made a cardboard carrier that fits tightly in the bag that has a shelf so the will be stacked four on top of four and I'm gunna use rolled up cardboard between the cups to keep them nice and tight so the font jumble around each other. I cut some breath slits too. It should work and I think I'm just going to use some polymer crystals the slow degrade kind that won't leach into the medicine. I've got a really good mix out there so I think it will do pretty well on its own. But I have a pump for backup. Plenty of peat and its real good soil out there found tons of worms working away and after about a foot and a half it's grey sand so with my added peat perlite mix and my amendments I think it will drain and hold the perfect amount of moister. The polymers work both ways when it's dry and if there's to much water it absorbs excess waiting for another dry spell if needs be. But pump is the plan b. the outdoor is just kinda my experiment to see how they can fend low maintenance. This indoors my medicine I'm gunna need for the next while.
Those outdoor babes oughta do great. You might consider tree donut bags. Treegator® Jr. Pro Slow Release Watering Bag for Trees & Shrubs I like the part in the desrippy about 
