The lotus I have now is from some seeds I got a couple years ago. It looks like you are doing it right, you have to scarify them to get them to sprout. I planted mine in a wide shallow concrete pot and it grew but never bloomed. I think that was because it was not in full sun. However, it also could have been that the pot was too shallow. There wasn't room for more than about 4" of dirt and a couple more inches of water. This year I have planted them in my roof pond in full sun and with about 6" of dirt and a foot + of water over them. They already have 5 or 6 floating leaves each and hopefully will bloom. The main thing to remember is that they are heavy feeders, I was putting 3 of those small miracle grow plant stakes in the pot every week!
