Bud leaves dying - Week 5 flower

[ScienceGrow]

Fifth week into flowering
Sativa dominant
Soil
LED 700W

Last fed fox farm big bloom full dose and tiger bloom half dose last Sunday.

This plant had high pH issues about a week ago, ca using red stems and ehat looked like a phosphorous deficiency. Thought I corrected it, it was looking healthier between saturday and yesterday.

Woke up to a very sick looking plant. Leaves are curling and cupping, turning a brown shade. They look like they're dying, and fast.

It's only the leaves on the buds, and only the upper, larger buds. Pretty sure it's not light, I actually moved that up the other day. Hasn't been fed nutes since last Sunday. Was getting water tonight.

Not sure what happened. Any ideas?

This blows. I know probably extreme nute burn, and I should flush and pray.

Any help appreciated. My first grow, so close to harvest. Disaster.

 

[ScienceGrow]

Actually, maybe it is heat or light stress. Doesn't look light nute burn. Has only been under this light a week, maybe it's overpowered. Heat shouldn't have gone over 80, but I guess it's possible. I have good ventilation and a second fan blowing on the plant.

 

[ScienceGrow]

Turned out to be a nutrient deficiency. Hungrier plant than I thought.