Southern Ag makes a water soluble 05-11-26 that you add CaN and epson salt to make solutions for water. It comes in a 25lb bag. Easy to use and it has the directions on the bag on what to mix. Should be able to find at most any farm store (CO-OP here carries it).

Also SouthernAG has a distribution center in Hendersonville so you could drive up there and save on shipping charges. If you don't want to make the hour or so commute, go to a landscape supplier and buy it from them. My bag was $35 vs $25, I believe (been a few years) and they can sell you the calcium nitrate you need too (water soluble/greenhouse grade)
BTW, I live just south of Greensboro, so I can relate to your weather.

Get the 5-11-26 and CaN and Epsom, works great and you will save lots of money!

Hey OrganicGardening,
I understand your pain in scouring the Internet for information on organic nutrients in hydroponics because there isn't much info on it and that isn't by accident. Hydroponics and organics don't mix well at all. Many hydroponics growers have a lot of problems with bacteria bubbling and foaming up in the reservoir causing root rot and the like. I wouldn't recommend organic products in hydro at all. However if you really want to do hydro a good brand is Fox Farm. It's pricey but extremely good for hydro. If you want to stick to organics I recommend General Organics GO box which is a line of organic nutrients only meant for soil use. Hope any of this helps.

The "Earth Juice" line of products might work for you. You would probably want to filter out any clumps before you add it, though. They are organic nutes, but be prepared to be grossed out if you read the ingredients list; there's a lot of dead animal parts in it.

"organic" nutes in hydro sounds like crazy talk to me. but then a fool and his money are soon parted.