I got about 60 pickeral pond weed seeds {Ebay}, yes it does take 30+ days to germinate in a container of water. You then need tweezers to put the little seedlings in a container of soil & keep it very moist. Use a very fine potting or pond soil, I used some cheap course soil & lost some seedlings. I have about 15 little plants at about a dollar a each.
Got four bare root plants {Ebay} easier to get growing @ $5 each & a gift pond lily. They have rather quickly started multiplying in the gallon pots I planted them in.
The bare rooted plants are much more predictable, easier establish & multiply faster.