yes, i do that every winter. my day temps tend to be warmer, but my nightly lows approach 39f sometimes but tend to be around 43-50. some orchids do just as well, as attested to the spikes coming up right now. i try to do some research though and choose plants i suspect can take it, due to their ancestry. there are some tricks, my balcony is very sheltered from cold wind, and when i know it will be below 45 at night i do not water at all. some of my plants go a week and a half without watering. i have had some damage to young leaf tips on some oncidiums like twinkle (especially the yellow one). others love it.