I wouldn't put ferts on the leaves of terrestrial plants, I don't think they can absorb anything that way, and worst-case scenario, once it starts to die, the ferts may actually damage the leaf tissue.
It wouldn't hurt to mist them with plain water though, and a lot of plants like the humidity from that.
How is your paludarium set up? If the plants can get their roots into the aquarium water part, you could just ad ferts to the tank like any other planted tank. If they are in separated beds/pots/whatever, then you might want to add something specific to those pots, but be careful that it doesn't wash down into the aquatic part.