Growing Summer Vegetables in the Winter?

This summer I didn't get a lot out of my garden due to all the wet weather and me having surgery. I am wondering if I can raise summer food in a greenhouse? Or does it have to be winter vegetables? I'd like to have more tomatoes, peppers, onions, etc. through the winter without having to pay a fortune for them in a grocery store.

Maybe it needs some solar heat? Does anyone know how to set up solar heat? The greenhouse I'm talking about isn't anything fancy, just a few boards and plastic. The idea here is to save money not waste it. Thank you.

Hardiness Zone: 7b

By Beverly from Havana, AR