Chiesel strain growing

Hey people this is my first time growing, am a newbie but my chiesel plants are 4 weeks and growing healthy i was wandering if anyone can give me tips and advice for this particular strain, like for instance how low can my 250 f lights go and is 2-2-4 a good fertilizer solution to give them.

also is miracle grow potting mix an ideal medium by itself.

anyone who grew chiesel before let me know as i am not really sure when to start flowering phase

why is the leaves curling under and some tips yellow and brownish
help dont want them dying