My Java Fern won't attach to my driftwood either but attaches very well
to rocks, particularly sandstone which is very porous. It can be tied to
the stones with thread or monofiliment but it will attach just as well
by just setting the rock on top of some of the hair roots - NOT the
rhizome. Having them on rocks also makes them easy to rearrange as
needed. As they get large I just add another rock along side and they
eventually creep over and cover it. I would be very careful dosing a
tank that small with fertilizers.