Homegrown.

Lately I've been hearing a lot more about individuals growing their own veg. I've been wanting to grow my own fruits and vegetables for a long time now but have been limited by a small balcony that only gets a few hours of sun a day.

My question is: if everyone household with the space to do so grew one type of fruit/veg plant how would the excess affect our world. Meaning, when the plant produces more than the household can consume and extras get sent along to friends and neighbors. How less dependent could we or would we be on grocery stores (mass growers)?