i buy the ones at walmart in pet department, their called lily bulbs, they say "live aquarium bulbs" at the top of package. it contains 2 bulbs, costs about 3.78 and if they dont grow send em back and they send u more.
mine have grown, within 3 weeks the leaves are 6" and its in sand. it attached itself into the sand. i just dropped it into the tank.
but last weekend, it grew a spout in the middle, so from friday night when i noticed the new sprout in the middle, until monday morning it grew 18" !!! thats right, 18" in about 60 hours. i snipped it off.
they will reach the surface, bloom then flower . the remaining leaves are about 8" now. not all of the plant grows to the surface, so u can keep it under control. i love the purplish red leaves. im getting more.
it grew that way and i didnt add fertilizers or anything to help it. now i fertilize my tanks because of other plants
i highly recommend.