Common wisdom in the 70s was 2 acres (8000 sq m) to support a family of 4 with a healthy diet from a diverse and robust selection of crops in a temperate climat

Common wisdom in the 70s was 2 acres (8000 sq m) to support a family of 4 with a healthy diet from a diverse and robust selection of crops in a temperate climate. Apples, potatoes, corn/maize, wheat, beans, and fill in the rest as you wish.