I put a heater in January, and started my tomatoes and squash. We also put in some sunflowers. All have grown beautifully. I can use this greenhouse year round.
In our greenhouse we grow all indeterminate varieties of tomatoes and peppers so they can be trellised up and we grow flowers up middle walk way to add some color.
My greenhouse offers me fresh peppers and tomatoes throughout the summer that i wouldn't get to grow in the Newfoundland climate. In addition, it extends my season and i get so many that i get to enjoy them throughout the long winter in Salsa, fermented recipes and dehydrated.
After a rainy summer like last year, I was able to get a good harvest of tomatoes and peppers in the greenhouse, while my outdoor plants mostly produced rotten fruits.