The plant look very good for a new grower to be honest,looking at the leaf blades ,un-less there 100% of very high in sativa genetics then the reason that the leave blades are really thin like that is heat ,too hot.
The other problem well i go has far has to say the main problem is the size of the pots ,plants of that size should be in large tubs,and by putting them into larger tubs i think you will prob find that most of the problems will be rectified.
The yellowing in the plant tops is nothing other than new growth .
But other than that get them on a decent amount of feed and i think that you will do fairly well from them,height may be a issue though so,make sure that you take this into account,when you do decide to flip the others,a friend had simular looking plants other month,and his room was no where near big enuf for them i got round this problem by re potting them,by laying them on there sides,and putting a table over them.[scrog table]
There doing fine now so may be worth thinking about,i would not do anything nutrient wise other than getting the 2 that are on there 2nd week of flower on a 2nd week pk spike like big bud,But most of the problems lay with the size of the pots.
Hope this helps tyke
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