Welcome aboard the Banana Express.
You have made the most common of mistakes that even pros fail to pick up on.
When we take our plants indoors, we place them in front of a sunny window. Makes sense, right?
Wrong!
Modern windows contain low E glass that filters out UV rays. All season long, our plants and trees get used to sunlight without any danaging UV rays. When we place them outside, we wonder why they turn brown and die. It's simple.
They got sunburned!
Keep your plants in a sunny environment that allows all of the cancer causing UV rays to bombard them, and you'll not experience any stress when you put them back into the real world.
It took me 20 years to figure this out, BTW. Egg on my face.