Could you explain when use 'turn' when use 'grow' or they are the same anyway? I do not feel the difference at least here and the like.
And the fields have turned brown. As the evening sky grew dark.
Turned typically conveys a change from one state to another, perhaps without any transitional state, for example:
The fields turned from green to brown.
His face turned red with anger.
Whereas grew may describe the gradual transition to another state, as something develops e.g.:
As winter approached, the nights grew long.
This is in the dictionary. Grow means to become something and turn is used for growing things that turn color, usually foliage but really any plant as autumn comes.
Merriam Webster: ENTRY: grow
: to pass into a condition : BECOME [caps not mine] grew pale
Merriam Webster: ENTRY: TURN
6a(1) : to make acid or sour
(2) : to change the color of (foliage)