If you have true aquatic plants they usually do well with light and a bit of iron fertiliser. They will need other nutrients like carbon dioxide (CO2) and nitrogen but most of that will be produced from fish food and waste in the water.
Normal aquarium lights should be fine but plants do best under light with a temperature or Kelvin (K) rating between 5,000K and 10,000K. The lights should be on for about 12hours per day. You can have them on for up to 16 hours per day. If you get lots of algae growing then decrease the photoperiod. If you only have one light on the tank and the plants aren't doing well then put a 2nd light on it. You should notice a huge difference in their health.
Normal aquarium gravel is fine for plants.
True aquatic plants are unable to support their own weight when removed from the water. Marsh plants can support their weight when out of water. The exception to this are the swordplants, crypts & Hygrophillas. these plants can grow under water or above and usually have pretty tough stems that allow them to keep standing up when removed from the water.
Good plants to try include Ambulia, Elodia, Hygrophilla polysperma, Ludwigia, Swordplants & Vallis.
