The white top growth tips do favor light intensity using too much light will make them consume more food. Roots may not be able to keep up yet, smaller plants, due to age. I'd back light off about a foot and top with worm castings and humic acid water that in with a water soluble fulvic acid. Or just back light off. If fading from bottom spreads start a feeding regiment if the white tips spread back light off some more.
You shouldnt be showing any deficiency signs yet. Young plants in organic soil. You could be showing nutrients burns which is also what those burned tips could be. If that's the case your ph is probably off and plants are starting to lock out. You know your grow better than I do. I'd check soil ph especially if you've been phing, idk about your soil but most organic soils dont need phing until soil is depleted of nutrients and you start using liquid nutrients if you use them.
