I've been doing my reading from "Wine Grape Production Guide for Eastern North America."
I have flat land that is rectangular and I can just as easily go N/S as I can E/W with trellis construction. From the book it says N/S gives better sunlight and it also states in the Powdery Mildew area that E/W for better air circulation.
Would most of you place your trellises N/S or E/W, if there were no terrain issues?
I've got my rows oriented 15 degrees west of north. I read somewhere that someone had done some calculations that this was ideal but no research had been done to back up those calculations. Figured I'd try it