The Medicine Man
Head Hydro Honcho
Just came across this nice piece about feeding iron sulfate to seedlings. Thought it might be of interest to you folks, too. I just ordered 4 pounds of it the other day to fix a deficiency, and then found this article, so I'm definitely going to be following what they did.
http://www.plantphysiol.org/content/55/6/988.full.pdf
http://www.plantphysiol.org/content/55/6/988.full.pdf