Burned leaf tip

Too much N, not enough mag to move it around the way it's needed and it's building In the tips. But, your main issue is you need to fix mag. Use a spray or add a calmag into ur sub. Good luck.

A combination of too much nitrogen and a developing magnesium deficiency. Not a lighting issue.

hello bro, its not a big problem she just had a lil bit too much nutes to take in,, my plants always have that after a 'good feeding'.. (so i know next feeding to give a lil bit less) good luck

Hey growmie, this looks like a magnesium deficiency. Calcium and Magnesium are needed in bigger amounts when growing with LEDs most of the time, especially in late veg and early flower (during the stretch) I suggest a CalMag supplement for this grow. For your next grow you could prepare the soil with amendments like raw gypsum (calcium sulphate), ultra fine basalt or granite rock dust (besides calcium and magnesium it will provide many micro nutes like iron, copper, zinc, silica,... aswell), , epsom salts (magnesium sulfate) and garden lime (calcium carbonate) . Its good to have those 4 + a CalMag supplement on hand anyways for every grower in my opinion, especially when growing with LED´s which for some reason force a higher demand in plants for calcium and magnesium. Good luck and happy growing!