What is the goto source for free-as-in-freedom information about growing plants and helpful diagnostics info?

I'm looking for a place to find any special info on soil nutrients, and simple image comparison type diagnostics. Something like the Wikipedia of a farmer's almanac or something. I'm looking for the best public commons type sources with no ulterior motives or influences; farm nerds for farm nerds.

I'm not looking for copy and paste articles, ads funded nonsense, or anyone that is influenced by sponsorships or product reviews of any kind.

If I have holes in the leaves of my tomato plants, or want to know the ideal lighting conditions, or soil pH, or hydroponics versus potted watering regimes, etc., I want to know where to look for info with everything from basic to advanced academic level depth.