I'm on the north shore of Lake Ontario. I used to have three ponds deep enough to overwinter everything in situ, but I have moved and have only a tub at this time. I lifted the Nymphaea candida today, took it out of the pot, washed all the soil off the roots, and placed it in a 'right size' Chinese pot filled with water. I have no minimally-heated area for cold storage of a potted lily. Should the pot with water be kept in the dark, changing water once a week, say, or have full light like a tropical water lily would?
Is this a fatal error?