See how the leaf is curling up? The burnt tips were there already that’s when I stopped the chems and went organic. I am making some tea for it as we speak. This is my first couple of harvests with LED lights. I used HPS in the past and think I’m going back. I experimented with them and in a few years as technology advances and they get the diode combos together they will be great.
What are your temps and humidity? Sometimes the leaf curling up is a heat issue, or too dry, or both.
If that is all in range, it could be continuing signs of overfeeding. Third, it could also be the lights are too close! Or a little bit of all three even, as I have had this issue myself.
As close as you are to finishing, it is best to resolve this problem because one time I had this around the same phase you are at, I did not fix it and my yield suffered greatly because they could not finish to full term.
From looking at your comments in this thread, my first guess is overfeeding.
Those are the three main culprits for tips curling up however, at least in my experience.
And for lighting, I am so in the same boat as you! I have grown with hps, leds, CFLs.... so many pros and cons to every setup, it really is a total personal choice at the end of the day.
I would check out
http://www.growweedeasy.com Nebula is an amazing grower, she has magnificent skills! Check out her section on lighting, she does grows side by side with various LEDs and stuff, definitely worth a look.
That website definitely should be a bookmark.