Blackwaterguy, Thanks for the info!
Please excuse crude diagram, but do you think this would work if I could get the leaves to stick out of the water?

... it can be a serious challenge to convert to submerged growth and keep it alive. I'd personally just consist it a terrarium plant (which is how I plan to one day keep it).
Bolbitis heteroclita
Ok. Awesome info. Redesign: I'll use a pot for the bottom. for the top I'll use one of the little dishes that you typically put underneath. A skimmer of ecolite in the top dish, set little driftwood stick on top of that, tie fern to stick. Give the leaves a little air to breathe.Aquatic ferns typically like good water circulation and having it in the pot wouldn't allow that.
Jeff, I appreciate simplicity and if the fern were my only issue I'd probably go that way. As is, I have 6 male guppies and soon to add 1 male betta in a 10 gallon tank. I'm hoping the added hiding spaces will make it easier for everyone to survive, so the Plant Jack/cave idea has turned into a 2-for-1 solution for me.You know, you could just float them on a piece of wood weighed down a bit to partially submerge it or tied off to a rock on the bottom with some fishing line.
Jeff.
AWESOME idea by the way. I was going to use hemp and just hope the roots took hold before the string rotted. In light of your super-helpful idea I will use a little bit of coated super braid and untie when I need to. I'm sure it will be very inert in the aquarium....tied off to a rock on the bottom with some fishing line...