Food

To produce 3000 calories/day, conventional farming requires 22,000-44,000 sq ft (0.5-1 acre/person), depending weather you are vegetarian or not (Vegetarians take less land). Biosphere II demonstrated that 1 persons caloric intake of 3000 cal/day could be done in 3400 sq ft, which is approximately 1 cal/sq ft garden.

John Jeavons, a foremost authority on bio-intensive farming techniques, suggest that one could meet caloric needs on 4000 sq ft/person using bio-intensive cultivating techniques. A city plot of 50 x 100 is only 5000 sq ft, barely enough room for feeding one person.  Adding 4 habitats to the land takes away much of the land space.

However, if you add vertical gardens to the mix, you have 3000 sq ft from the land and approximately2000 sq ft from the vertical gardens = 5000 sq ft garden space. That will produce  between 10 to 25%  of total calories needed, depending on the number of people living in the habitats (between 4-10 people. Not quite enough to be net zero for all food/person, but enough to be net zero in fruits and vegetables!