Mine is made with a piece of pond EPDM liner, holes cut out for plastic square pots, great stuff foam as a base and sheet moss attached to surface. Fish can not get to most of the roots since the pots are foamed in. I drop the round plastic pots containing plants inside the foamed in pots for ease of use. Very stable built this way, wind has not flipped one in three years. Teathered by a anchor point, also foamed in, to a weight so it can float around some but not enough to be driven into the lilies by strong winds.