Is it really that simple ? Simply place selected plants into gravel subtrate and then let them root into the gravel itself ? Would this work on a new tank thats only 5 weeks old ? Do you not have to feed these plants ? If not what do they feed on ???
Yes, it is that simple, if you have true aquatic plants. They get most of their nutrition by absorbing it from the water, rather than a soil like terrestrial plants do; the food they use is fish poo and wee; more or less the same as gardeners putting horse manure on their roses.
Of course, as with all gardening some plants (like weeds!) are easy and will grow away quite happily; others (like orchids) need more special care, lights and fertilizers and that sort of thing.