Lol shem,can tell your a concrete guy!I was a concrete contractor for 30+ years and been around it my whole life,dad was VP of a large ready mix company and every company i ever owned (3) was focused on that industry.The way i look at it a greenhouse should be energy efficient and as low tech as you can make it,K.I.S.S..When you start pouring slabs especially the way your talking about doing it (right) concrete is very expensive per sq ft,now add in supplemental heating systems and the cost to run them and you lose the efficiencies of a greenhouse or at least give your competition a competetive edge.By getting too crazy and drastically sending costs higher you reach a point where you could just grow under artificial light/environment almost as easily.Greenhouses are so great because they are low tech and take advantage of natural light and enviro,start pouring reinforced insulated slabs with hydronic heating and you have huge costs per sq ft when you bid it out,take my word for it,i have built many a tilt up for refrigerated storage facilities.From strictly a business standpoint the cheaper you can achieve the same or similar result the better and faster you can reach profitability and the better off you are IMO.
