Bulbophyllum outside in Summer zone 5b

[tombolo]

I am in the process of moving my Bulbophyllum outside for the summer, but I am a little concerned about the overnight lows. I am growing in Southern Ontario.

Occasionally, the temperature can drop down as low as approx. 12 degrees (lastnight) in the summer and then go back up to 25-30+ the next day (Celsius). I am mostly concerned with my warm/hot growers. Will they be ok outside if the night temperature drops low occasionally?

A list of some of the hotter growing Bulbos that I have:
Bulbophyllum macranthum
Bulbophyllum digoelense
Bulbophyllum gracillimum
Bulbophyllum grandiflorum

Does anyone have any experience growing Bulbos outside in these conditions? Any advice is much appreciated.

Thanks much.

[Ray]

They can probably tolerate 12C if dry, but would probably prefer 5 degrees warmer as a minimum.

[tombolo]

Thanks. I'll give it a go.