Is Space Needed for Farming?

Following on my post on Homesteading, I have been asked by relative if I did not find it counter productive to move back to Japan, if indeed, I wanted to grow vegetables. But just how much space is needed to grow vegetables? First, if I am to restrain myself on space I would just grow my favorite vegetables. Since I plan to move where there is no snow accumulation, and the temperature barely gets close to 0 degrees Celsius (Freezing point) , vegetable will grow and be harvested almost year long. Following the Japanese climate will allow me to rotate my cultures. With this in mind, I don’t think space will be a problem for my farming back in Japan.