I didn't grow U gibba, but they thrive like weed in my aquarium, I have to clear them out every time I get the water changed.
I saw people grow them in a shallow tray in the garden. Not too sure there is peat in the tray as the U gibba grow so thick at the surface and produced a lot of flowers. What I observed from the wild, the U gibba will flower when they grow thick and stagnant in the pond.
I placed my U. aurea and aldrovanda in the water lily and herbs pot in my garden, they thrive in there. The water is quite cooling as the pot was under some shade. The U aurea produced flowers quite frequently.