what is involved in making a 5g plexy bowfront into a desert terrarium

[bobc4d]

I have a 5g plexy bowfront aquarium I would like to make into a desert theme terrarium. has anyone converted an aquarium into a terrarium?

I googled and in general, it say to line the bottom with aquarium rock, then a substrate, then sand. why would I need a substrate for small cactus, wouldn't sand work? would I need holes in the bottom to drain any water?

thanks,
bob

 

[Tetra1990]

Would this be just for desert plants? If so, then you don't need drainage holes for excess water.