It all depends on your families preference to that veggie. If everyone loves tomatoes then grow an extra plant. If you were to plant in succession, say 2-3 of each separated by a week or two, I think you would have enough for your family. Also any access can go to your neighbors and friends.

Nobody knows how much to plant to feed a family of six. Heck I have family of 6 (if you don't count the dogs) and I couldn't tell you how much to plant.

It depends on what your family actually eats, whether you want it only fresh or if you will can, freeze or otherwise preserve etc.

Just grow some stuff and see how it goes and adjust next year.

Thanks. I want to try and can veggies, but I not sure if I can grow enough plants in containers for that purpose.

Here's a suggestion if all of these are popular with family members (I doubt you'll be able to grow this much in containers, however):
Number equals plants per household member:
Green beans 4-8
Sweet peppers 2-3
Tomatoes 3-6
Cucumbers 1-2
Zucchini 1-2
Onions as many as space permits for green onions
Melons 2
Blueberries 3-5

Here is a link that might be useful: HarvestToTable.com