I grow in soil, and have been for a very long time, depending on the strain leaf yellowing like the plant behind the other one can be naturally occurring thing, but it can also indicate a nitrogen deficiency or a buffering issue, what a lot of people dont understand about ph and the buffering issue is that an out of whack ph will mimic a nitrogen def, because thats exactly what's going on , the plant may have an abundance of nitrogen in the soil but can't utilize it due to the ph imbalance, or when combined with very strong lighting the plant IS uptaking the nitrogen but not sufficiently to keep up with the strong lights. so the issue gets a little cloudy when trying to diagnose from afar, but here are the pertinent issues,,ph your soil and your runoff. dial your lighting in,, if you suspect the lights ar too shtrong, or too close, reign that in. the leaf tip thing is almost always a nute burn, just small tips or brown tips and the rest healthy indicates the plant is healing, progressivly yellowing tips and other symptoms means the burn is ongoing and needs more attention, look at your new growth? still seeing tip yellowing, do a flush, is nt rectified after that do a repot to get rid of salts build up,,, it happens, even in soil, every once in a while i will have aplant who nutritional needs are a bit different than the rest and i will have to either repot or completely dial in the nute schedule, most of my nutes come from a combination of chicken poo tea and dressings of dolomitic lime and trace nutrients , worm castings, and blood meal, but i still get nute burn..and salts will build in the soil from the urea in the chicken poo and other amendments as well, soil doesn't solve all the problems but it softens the damage and gives you more time to react and fix things, so its a more forgiving way to grow.
