close to end problem;help?

[Cast]

I am near the end of this grow (my second) and some of the ladies, (2) are turning yellow and getting burnt tips and curling under. Here are the particulars: 1 600 watt hps, soil(promix,worm castings and perlite), temp is 83 to 87 with constant airflow and very good ventilation, I use a teaspoon of mgrow bloom to 3gallons of water aswell as a pintch of epson every 3 days and the rest of the time plane water. 4 days ago I started using prurple maxx and gravity with the plane water and I am thinkin about adding mollasses. this problem has been around for about 2 weeks and is slowly getting worse. thought it was mag def or nute burn but not sure. buds are still progressing but I would like nip this in the "bud" before it causes a loss in yield. any suggestions? sorry the pictures are not the greatest.

ps. I dont know if it matters but these are older than usual they were in veg twice as long as usual.

[Cast]

sorry, forgot to mention that the light is enclosed with an in line fan pulling air through the fixture and is about 12 inches above the tallest bud.

[Darkhosis]

I suspect overfertilization. A very common mistake is when you see leaves turning yellow/curling you think magnesium deficient. So people start pouring in nutrients making their problem worse!

If it were me I'd flush them out with plain water for a week and see if it starts to turn around.

Only other things I can think of is possible root rot. Have they been in the same containers for a long time? Other thing is fungus gnats or another pest.

[Cast]

Thanks for the reply! (this has been my first post) Yes thay have been in the same pots for about 2 1/2 months. How can I know for sure if it is root rot withoiut destoying the plant? and what can I do to save it?

[Darkhosis]

Originally Posted by Cast

Thanks for the reply! (this has been my first post) Yes thay have been in the same pots for about 2 1/2 months. How can I know for sure if it is root rot withoiut destoying the plant? and what can I do to save it?

It's easy bro! Just lift the plant up and if you see roots coming out the drainage holes then that is it for sure. If you're unsure cut a small hole in the bottom. When you transplant you'll REALLY be able to see what's going on. If they were root bound/rotting then you'll see how they've spiraled around the bottom.

Good luck man, and yeah does sound like it's time to transplant into something bigger!

[Cast]

Thanks man! I checked the roots and they are fine so I am suspecting nute burn and it has progressed a bit since last night. I wont be giving them any more nutes ( I didnt think i gave them to much to begin with, oh well). I adjusted the ph it was a little high it was around 7.8 I brought it down to a 6.2 for now. I also added some molassess to the water along with the maxx and gravity. I read that molassess helps with adding energy aswell as micro nutrients which i have never messed with. What are thoughts on micros and molassess?