Depends on the area. If you're in a densely populated environment, it's going to be a mess. Depends where you live but what we in Toronto would consider "cottage country", so perhaps 1-2 hours north of the city is reasonable for most places I would think.

Even 1/3 acre could be enough for most people. Check out growingyourgreens on youtube. I vouch for John.

The further you get out the better obviously but we need to make compromises that's for sure.