Bulbophyllum outside in Summer zone 5b
 

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.

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

Thanks. I'll give it a go.