cut a peice of acrylic and seal around it with silicon as done here:
http://www.plantedtank.net/articles/...to-Journal/28/
crypts would grow good in both parts. but if the ones on land flower, cut of the bud before it opens. the blooms smell like rotting meat to attract flies for pollination. you could also grow emeresed anubias, java moss, hairgrass (any kind i think), and HC.