Exactly as JSB said...should be no need to cut a hole in the netpot...besides, your roots shouldn't be so thick in diameter than that they can't crawl through the openings in the netpot? If they are, smaller roots will just branch off that are small enough to fit through...it's just a part of the process waiting that first day or two for growth to skyrocket. There may be a way around it I suppose, like if you could pull the roots through the openings before you fill in your hydroton. But you just have to be careful as roots are pretty delicate and breaking some may seriously stress your babies.