For the last several years I have been using a mini-greenhouse to extend my kitchen gardening season.
In the spring to harden off seeds that have germinated indoors and in the fall for containers of tender peppers, and more hardy onions and kale as well as herbs like parsley and sage.
I also use it to transition house plants back into the house for winter as well as plants that I use for cuttings for both indoor pots and to transition outside for ornamental pots next year.
My mini-greenhouse also extends shelter for ceramic pots and garden items that may be sensitive to the freeze thaw cycles and the elements.
It is truly mini at six feet wide and eight feet long, but figures big in my plans for a salad garden this holiday season.