At times I work for my brother in law, he has 9 greenhouses if I count right from memory. He has several different styles, from home built wood Cornell style at 27 by 75 to salvaged 21 by 40 short squat hoop house (a real snow load issue with these, that's wy they are salvaged) he just started crops about 2 weeks ago, still getting in plug orders. Love seeing spring in the houses before it comes outside. The soil where he is is a sand clay mix that holds water terrible. The Cornell houses are having frost heaving problems with the posts, broke a rather, will have to do a drainage project sooner or later. Oh well.
Eric