What Nutrients do the professional growers use.

Hello All,
I would like to apologize 1st because I'm sure this question has been asked before. What nutrients do the big boy's use? Do they use commercially available nutes or their own mixture?
Thanks for any replies!

'Pro growers' running warehouses who actually understand plant nutrition are likely using giant sacks of raw salts and/or something like jacks/peters to keep costs low. 'Pro growers' who run one-man operations are likely using highly concentrated liquid foods because dry foods are time consuming and a PITA to work with.