Less than you need to rent in Manhattan, which is presumably their target market. I have a little less than 0.2 acres, and I've got 11 in-ground trees and another ten container trees. And I'm purposely keeping the property looking like any other house in our HOA, rather than planting things super close and dwarfing or espaliering them so that it looks like an experimental farm.

Granted some of the trees are actually on our neighbor's property (with their blessing), but still.