Artichokes are a member of the sunflower family, and like all members of the family, they love heat. They thrive in temperatures from 60 to 85 degrees Fahrenheit, with average temperatures of 70-80 degrees being ideal. The key to growing artichokes is to keep them at a high temperature for a long period of time. The heat causes the leaves to grow upward, causing them to blossom and then produce more leaves.
This means that if you let them sit outside during this process, you will have to remove the old leaves.