I know that bringing plants from +20°C to -10°C can cause a lot of stress, because they need time to adjust to cold temperatures.
Does it work the other way around too? In other words, is it ok to bring indoors (+20°C) a plant that was kept outside (-10°C) the whole winter?
Some background: Most of my plants can handle temperatures between 0°C and -10°C, but this winter is unusually cold, and this week temperatures might drop down to -20°C. I'm afraid that some plants won't be able to handle it, but I'm also afraid to bring them indoors where it's 30°C warmer, because such an abrupt change in temperatures might harm them. Is it safe to bring them inside? If I do so, should I keep them indoors until spring or can I bring them outside again once it gets a bit warmer?
The plants grow in containers on my balcony, if that's important.
Update: I decided to leave the plants outside in order to not stress them and all my plants froze and died. I think keeping them indoors at least during the nights would have been a better option.