Who knows. I don't think I've encountered a "problem" just yet...I've only had them for about 2 months and they were bag babies (albeit with huge roots systems and growing well out of the largest sized bags the company provides) so it's understandable that they haven't bloomed yet. I'll just have to wait and see. I find it hard to believe that I couldn't bloom a Vanda in my windows in Texas, when I've read several online postings about people in Canada and the UK being able to bloom theirs with no additional lighting.