I've been learning the specifics of biointensive growing lately, which I was just kind of fudging before, and it's been really enlightening. With good loose and fertile soil you can plant things at the within-the-row spacing each way, in wide intensive beds instead of single rows. So, say the plant likes 4" between plant in the row, and at least 1' between rows. In a 4' wide bed you could put like 16 rows of plants offset from each other with every plant still 4" apart. It takes well worked soil though, really really thoroughly wetted then totally dried for a couple days before digging, 1-2" of compost added on the whole thing, the top 12" dug and broken up with spade and fork and the next 12" down dug and broken up, those 2 layers not mixing. Organic fertilizers applied appropriately, and no pesticides, with companion or rotational plantings carefully chosen to keep up soil fertility. Done right it's supposed to increase yields of each plant and decrease work and water and nutrients required overall.