I liked how my 37 turned out with the Soilmaster Select substrate, so I decided to give my 3g betta tank the same treatment (and a few plants to boot). The two bits of java fern on top of the helmet have rocks that the rhizomes attached to in the tank's previous substrate. I'm hoping they attach to the helmet too.
I'm not sure what the tiny plant is in the background. Maybe some type of sword? I'm looking for something to grow vertically.