Problems with leaves during bloom stage

[Smallgrow]

A reminder about amount of light and environment/nutrition that I struggle with.
Most of us have plenty of power in our lights, it’s natural to want to throw that at your plant as all things being on point you’ll get more and better results.
However , the more light you give the plant the more critical it is to have everything else perfect. 750ppfd and above is only good if you have everything else figured out, otherwise it will cause problems as your really pushing the plant at those levels.
Keep you light at a recommended distance and at or below 700-750ppfd, once you’re having perfect runs repeatedly then start bumping up your intensity.
Im currently running about 650 at the 4th week of flower (approximately the peak of flower light wise) I will start to lower it as I head to the finish line

 

[Bluey]

I agree. This light doesnt burn. Have 2 here.

So start with the basics.

pH first. If in soil and you've been giving it at 6.0 go up to 7.0 now for the next feed then 6.8 then 6.5 and back up and to 6.8. Maintain 6.5 to 6.8. Vary it

Nutes. Tell us what you are using, how much (EC preferably), in what sort of water.

Temps, RH% and air movement.

Given your problem is coming on soon after flip, how you are managing that and the nute transition may be a factor

 

[Bluey]

That's good advice, the more light above 750 on many genetics the more difficult to manage. This advice only applies to full spectrum LED's. Outdoors and under HID's different again

Managed well though you will find it is also very much strain dependant. Some will max out around 750 to 900 before becoming difficult to manage, some sativas will handle 50% more than that.