Join Date: Oct 2010
Location: Victoria, Australia
One method is that if you use a HOB filter, you can remove the filter lid and grow the plant directly out of the area that contains the filter media. Some people also choose to baffle the filter with some aquarium sponge and then attach moss to this, as the constant water flow from the filter keeps the whole area moist.
There are lots of aquarium plants and bog plants that can be used successfully in this manner. I think I saw someone growing some kind of orchid out of the top of his filter along with a pothos that had been trained along his light stand.