When it comes to buying vegetables, there are several purchasing options. Fresh from the grocery store, fresh from a garden/farmer's market, frozen, or canned. Not all vegetables are the same!
Your best option is to grow the vegetables yourself, or buy them from a local grower. This way, you know the produce was picked when it was fresh, grown (hopefully) organically, and you're helping your own local ecosystem and economy. Nothing seems to taste better than a vegetable you have grown yourself, and kids really love being a part of the process. As I begin my own garden, I'll blog about this subject more.
Buying in-season vegetables from the grocery store is your next best bet. If they are in-season, they are more likely to be picked when ripe and have more nutrients than having them ripen off the vine. If a vegetable is not in season, you are usually better off buying it frozen. Frozen vegetables are picked at the peak of freshness and keep almost all of their nutritional value. They normally don't have any salt added and are a great way of getting exposure to produce you don't have easy access to in your hometown. Steaming is the best way to prepare both fresh and frozen veggies to retain the maximum nutrients.
For many people, canned veggies seem to be the easiest and most economical choice but, unfortunately, they are also the worst choice. During the canning process, vegetables lose many essential nutrients, and in many varieties, a lot of extra salt is added. Plus, they just don't taste as good!
For the most part, we stick to fresh and frozen produce. I do purchase canned beans when I don't have time to prepare dried ones or I can't find the dried ones that I want. My family also has a fondness for La Sueur Early Peas (I get the 50% less sodium kind), so I do cave in and buy those. Otherwise, we try stick to fresh and frozen and steam them. I believe most children will like vegetables more if they can taste their true flavors.