I purchase the Aqua Plant Bulbs that come in a variety at Petco which includes: Aponogeton "Aponogeton Ulvaceus" (Betta Bulbs), Onion "Crinum Taianum," and Waterlily "Nymphaea Sp.".
I use Fluval Stratum which is natural dirt in pebble form that helps aquatic plants flourish along with a proper amount of lighting. I have standard LED lights in my tanks. Two of my tanks are bright and one is a low light, yet it still grows any bulb I anchor in the stratum. I emerge the bulbs halfway so they can find the light and still get the nutrients in the stratum.
I have a carbon base filter which helps plants grow, but they need food like any other plant or animal does. I use the brand API Root Tabs, API Leaf Zone (Aquarium Plant Food), and API CO2 Booster. Within a week or 2 my bulbs are sprouting and it's fun to watch! My bulbs grow an inch per day and already start to propagate within weeks!