Originally Posted by Richard

Steve, I think you should try again but make sure that for hydroponics you use a fertilizer that is labeled "Urea Free". If in doubt, look at the "analysis" section on the label where the Nitrogen components are listed. If one of them is Urea, then don't use it for hydroponics.

On the other hand, urea (which is made by extraction from the atmosphere) is an excellent nitrogen component for many types of plants growing in soil.