WeGroanswered grow question 3 years ago Since you claim the leaves on the upper plant is getting this yellow tips, aswell as what i can see in your journal, the outer-edges seem to be curled upwards the higher up they are on the plant.
This indicates light stress.
the same plant also has very dark green leaves on the lower part, that indicates that you might be overfeeding that plant. At this point, its not to much, but there is something to take into account becouse: the plants to the left in your grow tent seems light green, almost underfeed. My guess is that this is another strain that has a bigger nutrient need.
so in conclusion:
the burnt tips are becouse of light stress. put more distance between the light and the plant.
That plant ALSO >almost< has to much nutrients.
your other plant/strains almost has to little nutrients(light green) and if i was you i would feed them with different EC nutrient solutions.