The pics below are shots of the prototype grow tower, made of 6 inch PVC pipe, 8′ tall, which showers 36 net cups with nutrient rich water to feed single stalk plants such as Swiss Chard, Spinach, Romaine Lettuce, etc.
The center of the greenhouse will have two rows of these, 24 grow towers each, which will be planted in stages, continually providing over 200 heads of lettuce, say, per week. Total heads of (lettuce) 1,728. Square feet consumed by their footprint?: 100 = 17.28 heads of lettuce per square foot. The cost to build each one, not counting labor is around $70. At $2 per head of lettuce, the tower pays for itself in 3 months of production.
And here is a smartphone pic of the San Francisco International Airport Terminal architecture for inspiration:
