tbh, thats wrong...
the holes are just there to provide drainage at the right level for runnoff to prevent overwateringyour plants...
the oxygen get to the roots from the water... the "dissolved oxygen" in the water (DO)... the more DO, the better/faster the root growth you'll get... thats why its a good idea to keep an air stone in any rez's of water and/or nutes you keep stored around... DO is high straight from the tap but only hours later quickly reduces to much less efficient amounts...
thats the reason why hydroponics works so much faster and more productive than soil grows... they're able to provide more DO to the root systems... soil pots stay damp normally for a few days on end... watering generally is only done a couple times a week, which means that the water in the root system is not nearly as good the 2nd or 3rd day soaking as it was the first... with hydro you're getting fresh water (fresh water means oxygenated water) usually daily if not multiple times a day...
plus nutes can generally be better controlled and dialed in in a hydro grow than in soil grows...
anyways... back to the hempy buckets... they are basically manual flood systems, flooding generally everyday/every other day...
the holes on the side are not bringing oxygen to the roots..
... and please, i hope this doesn't come off as mean or snobbish or anything, i just want to make sure the correct info is handed out...