1- Should I trim/cut the Yelow leafs?
2- Should I give them nutrients already?
3- How much lux should they have at this stage?
4- Should I transplant them to a bigger pot? (I did with one)
5- I have coco fiber (picture at the end), should I mix it in the soil with perlite?
6- how much humidity should the tent have?
Thank you very much guys. This is the best community ever.
How old are they? You main problem looks like they canβt flourish, they look like they are struggling.
This is usually caused by overwatering, but inn your case it looks like the earth is really compacted. The earth should be really light and airy, with lots of spaces for air pockets and roots to grow into. If it is squashed down (either by pressing or too much water) the roots cannot breathe and growth is stunted.
You will also see deficiencies because they cannot take in nutrients effectively.
To answer your questions:
Only if they are dead
You can start but only with very weak solutions at this stage (under 50% strength)
You can google ppfd charts but at this stage 2-400ppfd should be plenty.
You could do, but first learn what your mistakes are so you donβt do the same things over again.