Welcome to The Easy Garden,
@frontiergirl53! I'm glad you found us. Good question. We like members who jump right in and take part in discussions with us.
Caveat! I am a teacher. When you ask about generating heat, I think of rubbing my hands together very quickly, pulling my brother across the carpet, or setting a match to some kindling. What you want to ask is what are the best ways to retain heat or keep out the cold.
Depending upon where you live, some members have found row covers to keep cold weather crops growing. Occasionally they will add a blanket for added insulation on the coldest nights.
Hot caps -- because of their smaller size -- are usually used in the spring to get a faster start with seedlings rather than to extend the growing season.
Cold frames can be very useful for early starts and late season extending. By adding a thick layer of manure or hot compost under the planting layer, you can add heat to the growing plants. Be sure you are available to vent during the day if you want to try growing that way.
We all have different gardening challenges and we all have found things and techniques that work for us in our gardening situation. I am sure others will be able to help you with suggestions. Good to have you growing with us.