I've got burn questions about fertilizers.

I've got a lot of old liquid fish mixes and micro nutrients , From my
hydroponics . I used them last year in my outdoor soil garden . The bottles
of fish mix say they wont burn. One is 5-1-1 and the Alaska starter fish
mix is 2-1-1 . I know they are only 100 % ground fish mixed with water , It
looks like syrup and stinks. Last year my garden did very good on it. I put
about a half a shot glass with about 2 gallons of water and hand water the
plants. Maybe three times for the summer. My soil was N deficient.

Just so you know .It wont burn. No matter what. Or how much.

What's the reason some fertilizers wont burn,. Is it just because its dead
fish. Or natural or something. And if it wont burn, Why isn't non burning
fertilizers available in the big stores.

What else could be used as non burning fertilizers?

Thanks

Diesel.