Ouch.
So, hempies... Instead of measuring up from the bottom when deciding where to make the hole, one should be measuring down from the top?
Mixing in a quantity of vermiculite might help (significantly) with the wicking issue - but it could (in practical terms) make the compaction issue worse, and might add a bit of an "alkaline pH burden" to the equation.
Aerating won't help extend the wicking distance. OtOH, if one decides to make the hole at a higher level (which would help, in a manner of speaking), it could end up causing lower levels of oxygen down there - and aerating would help with that.
I wish I could remember why I ultimately stopped using vermiculite, way back when. There must(???) have been a reason, since I've still got ~1.8 or more cubic feet of the stuff. I know why I don't reach for it NOW, lol; the "ventilated" (seems to have some small holes in it, throughout) has been sitting on my basement floor for ~10 years, so it has been more or less constantly exposed to nasty water/etc. the entire time. I suppose I could throw some in the oven, spin the hate-dial all the way up, and bake it for an hour. Er, sorry, lost my train of thought.
No more than a foot... That seems to be in line with what Sue has told us about wicking in hempies, IIRC. Makes the two-liter bottles seem better and better, lol. Now I'm wondering about volume to height. After all, kiddie pools aren't all that tall
. 21.7 ft.³ hempy, anyone? (Don't look at me, I couldn't afford the materials.)Here's a thought: Take one of those 2' tall pots, empty it out... then take a piece of PVC pipe or whatever you have available that's of suitable length, stand it up in the container (off to the side), fill the pipe with vermiculite (I suppose you could use coco coir in place of vermiculite, but my gut - which isn't any smarter than the rest of me, BtW - tells me vermiculite would be more appropriate for this), then fill the rest of the container with perlite as per normal, wet everything down and, finally, remove the PVC pipe (perhaps using something in the pipe that you hold at a stationary height while you raise the length of pipe so that much of the vermiculite doesn't just come along for the ride).
Would that give you a built-in "water-wick," I wonder? Shouldn't really exasperate the compaction issue, since the vermiculite wouldn't be mixed all through the perlite.
I have a feeling this one will remain as a thought-experiment. After all, it'd be modifying a failed experiment in an attempt to succeed... when an alternate method obviously works. That'd probably only have an appeal if you really like the form factor of those 2' tall containers.
). I assume I could do the same thing by sticking the "holed" cup into one that was still intact, then lifting it back out after watering the seedling?
). I figure, with hempy, you are adding fresh nutrients every couple days or so, so how much does the plant really use during that period? 
) fill our bellies at intervals and then live off of that until the next opportunity to eat presents itself.