Picture posting is enabled for all :)
You have to find a way to stop the soil falling out and let the moisture in from below (capillary matting). I use several methods and haven't settled on one yet.
What makes a rootrainer a rootrainer and not a pot?
www.garden-roots.co.uk might be selling what you want.I have only just found them, and know nothing about them!!Caveat emptor!!