Take sweet potatoes, for instance. I cannot grow them all that well up here in the northern end of Michigan. Our evenings tend to be a bit on the cool side - I'm talking 50 degrees or less - and the daytime temps don't always get above 70. Toss in a very short growing season (we get a killing frost sometimes in August) and you have a recipe for not so good sweet potatoes.
What DOES grow well up here are peas, lettuce, spinach, green beans, and other crops that don't mind the colder nights. Tomatoes might make it until August and September, but most years they are a disappointment.
When you research, or learn from personal experience, you can easily find a great variety of plants that will grow well in the area in which you live and garden.
As I said earlier, peas grow amazingly well here. Below is a picture of snow peas I picked yesterday. They have been trimmed, washed, and placed in a pot of boiling water for two minutes. This blanches them so they can be frozen for winter use.
After boiling, they are rinsed with cool water to stop them from cooking further. They are drained of excess water.
I like to use Food Saver bags and vacuum seal the food that I freeze for long term storage. The peas below are not sealed until frozen. If you try to seal a bag right after filling, you'll likely find they won't hold a seal. The peas are too wet and the dampness keeps the bags from sealing.