A light soil like coconut coir wouldn't even injure then even if the tube was flipped. Maybe if it was shaken really hard some might die. I have seen that those who ship with charcoal use large chunks so that less shifting occurs and fewer are killed. Maybe a couple big pieces with tons of big holes in them or drill a bunch of holes will protect them better with charcoal. If Coconut coir would work I would ship in that. So much easier IMO.