I’m looking for some advice on growing spring bulbs in rooftop containers. Can you help? We want to play some bulbs this fall and let them sleep up on the roof all winter and then bursting with some early color up there.
Since our pots are 12-16″, there’s not much soil there to insulate bulbs over the winter. We plan on keeping out pots right along a white wall on our roof, which will provide a bit of insulation, but still it will be cold.
And then if the bulbs survive the winter, it can get windy on our roof. It seems like we will need bulbs with sturdy flowers and short stems. Does this mean French tulips, a favorite of mine, are out? Seems like we’ll need hardy, short stemmed flowers.
I’m planning on using the bulbs only once and then discarding them. This is not the most frugal way to garden, we realize, but we don’t have the space to keep the bulbs in our pots and there’s no cool dark place in our apartment to store them.
I really like the varieties of tulips that ColorBlends puts together, though their site seems to be down right now.
I also remember loving crocuses when I was a young child, so I think these would be fun. I was originally thinking of a pink and white color scheme, but I couldn’t find any short stemmed pink tulips . . . then I started liking these orange Orcas. They’d be great to cut and bring in the apartment and the color is great with purple crocuses.
Brooklyn Roof Garden 
Posted by Bill Pettit on August 21, 2009 at 7:44 pm
Hi, I planted bulbs in my roof containers here in Albany a couple of years ago and not one came up. the best I can figure is that the containers did not give enough insulation over the winter… Some years my roses survive and some times not.. as well…. I do think it is worth trying again however.
Posted by Marie Viljoen on September 8, 2009 at 11:38 am
I’ve found that tulips can rot over winter in containers with the freeze-thaw thing. That’s what kills. Daffodils have worked well, and the alltime winner, even in your pot sizes, is lilies, which are for summer of course. But champions and there are sooo many varieties.
I do not water my pots in winter unless it’s a very bright day. But I travel often for 6 weeks to 2 months, so they are totally neglected. If anything, I would suggest watering after planting and until freeze, never letting them stay in really moist soil – allow to dry out between waterings and then, when it freezes, cover the pot to prevent excessive snow melt and rotting.
I would also suggest planting some bulbs in late Feb/ early March, and see what happens.