I often answer gardening questions by referring to online publications from various Land Grant Universities. There is no reason that I should keep this very valuable resource to myself.
Therefore, bookmark this puppy http://www.searchedu.com/
In the 'search for' bar, type in what you are researching - for example (as I did for another post) "growing popcorn." In the 'using' bar, I used "education sites." This simple search resulted in 10 pages of ~10 references each.
Why use this site as opposed to Google of Bing? Simple, as long as you use "education sites," you are getting the results of impartial research, based upon the scientific method. You will not be seeing the grandiose claims for Grannie's Miracle Foo Foo Dust, you will be getting facts. Often you can get articles for your state about your particular question. If not, a state with similar conditions may have done the research to answer your question.
Go ahead kick the tires and see what you can find there.