Overwintering in Zone 3b / the utility of bulb pans

5 years ago

Hi all,

I just wanted to pick your brains re: overwintering bulbs in severe cold climates (zone 3b). It's my first winter here, but temps tend to dip down to -40 over the winter. I'm planning on planting some spring flowering crocus and species tulips in some containers (balcony gardener here). I have an unheated shed that's attached to my house.

I've read that it's the freeze-thaw that is far more damaging than the cold weather itself, so I was planning on putting the containers in the shed, which is somewhat shielded. Any merit in further insulating the containers inside a cooler, which will further buffer against changes in conditions? I was planning on buying some cheap coleman coolers on kijiji.

Does anyone here have experience with overwintering bulbs in containers, with the -40C temps?

In addition, any merit to bulb pans? I like how they save space and I can fit more bulbs in them, but I plan on growing these bulbs in containers for hopefully long-term. Can crocus bulbs survive in shallow bulb pans permanently (assuming I fertilize) or will they just wither away eventually.

Finally, I also have some lily bulb transplants. I built a big insulated planter using wood panels, lining it with building insulation panels, as an experiment. I planted some of the lilies in there, along with some siberian iris and perennials. We will see what happens in the spring! I have some bulbs left over - any suggestions on how to over winter them?

Thanks in advance!

Comments (3)

  • pitimpinai
    5 years ago

    Hi Calvin,
    It is really doubtful that you can overwinter those bulbs in containers in Saskatoon, unless you bury the containers in the ground.

    I tried bulbs in containers standing slone, bulbs in containers surrounded with bags of leaves and bulbs in containers in a cooler in an unheated garage. I ended with mush in spring no matter what. And Chicago winter is not as brutal as one you have in Saskatoon. I do wonder if the bulbs will survive if you set the cooler against the wall ajacent to your house.

    I have not tried planting crocus in bulb pans, so I don't know how long lived the crocus will be in them.

    I hope the lily and perennials in your special enclosure will make it through the winter for you.

    Good luck with your garden.

    xmpraedicta thanked pitimpinai
  • FrozeBudd_z3/4
    5 years ago

    I force bulbs in my well insulated unheated attached garage, though the coldest it gets in there is about -8 C while outside we're experiencing the most brutal severe cold that a zone 3 winter can dish out .... so, it's rather an ideal place for such a purpose and storing dormant stock such as potted roses. I'd venture to guess that your shed would become toooo cold and instead I'd sink the pots into the ground for the winter.

  • xmpraedicta
    Original Author
    2 days ago

    5 year update - you were both absolutely correct. The bulbs all rotted. The lilies in the raised containers didn't do well - the mature bulbs failed, but I had many small sprouts from bulbils that dropped down. The bulbils seem to do well for a few years but once they reach flowering size, the bulbs fail. I suspect the larger bulbs just can't tolerate the exposure.

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