Yellow Leave And Necrosis

[MrBlackThumb]

The problem started two weeks ago after I realized the soil pH of my Mental Floss was 3.2
I flushed it until it was back to 6.0 and the necrosis slowed down for a while.

Now, it's back in full force after I flushed the plant with mineral oil because I had 10 gnats flying around the plant.
The flush did kill all the gnats but now, the plant is dying at a rapid pace and i don't know what to do.

I tried flushing, correcting the pH, feeding and I even tried molasses.
Nothing works.

The worst part is, the exact same thing happened on my first grow and I ended up chopping the plant early because of it.
What do you guys think is going on here ?

What should I do to fix this or at the very least, slow down the issue for 2-3 weeks ?

1. Are you growing from seed or clones? Seed
2. How old are your plants? 2 months and 3 weeks
3. How tall are your plants? 1,4m - 1.8m
4. What size containers are they planted in? 3 gal
5. What is your soil mix?
6. How often do you water and what type of water do you use? every 3-4 days, tap water
7. What is the pH of your water? 6.0
8. What kind of fertilizer do you use and what is its NPK ratio? Maxibloom, 5-15-14
9. Do you foliar feed or spray your plants with anything?
10. What kind of lights do you use and how many watts combined? HPS, 400w
11. How close are your lights to the plants? 50 cm
12. What size is your grow space in square feet? 3x3
13. What is the temperature and humidity in your grow space? 76-68F, 42% humidity
14. What is the pH of the soil? 6.0
15. Have you noticed any insect activity in your grow space? Fungus Gnats
16. How much experience do you have growing? This is my second grow

 

[Seamaiden]

Mineral oil?

Fortunately, what you're showing looks like natural behavior to me. Maybe the plant is a wee bit hungry, possibly for K, but given what that main cola looked like, I wouldn't sweat it too hard.

You do know that they do this naturally as they progress through flowering, too, right? I mean, yeah, you can do things to keep them green throughout, but it's not necessarily what's natural to the plant.

Let me show you a photo of one of my girls really late season. I know that when I replant next year, my plants are going to have plenty of food and do the same thing as they reach the end of their lives.

 

[MrBlackThumb]

I know it's normal for leave to turn yellow and die late in flowering but this is different.
The brown stuff I showed appears all over my plant, it's even killing tiny bud leave.

This thing is ruining the bag appeal of my bud and that's what bothers me the most.

 

[Natural]

mineral oil seems extreme for fungus gnats..I bet those roots are coated and cannot breathe after that. For such a small garden..you could easily put a 2-3 inch layer of diamotaceous earth over the soil..or sand and perlite, or even super fine steel wool..that would slice up any fliers trying to lay eggs in the dirt or leaving the pot. If you really want to get crazy you could dilute 1:4 3% food grade hydrogen peroxide to water, and try and soak the top 3-5 inches of soil to kill the larvae. It will kill any beneficial bacteria as well..but turns into water and oxygen quickly and won't harm your plants.
Also, for the ones flying around..to kill them use yellow sticky trap paper or leave out a partially filled glass with a bit of apple cider vinegar or wine..and they will come drink and drown.

 

[MrBlackThumb]

I'll try the apple cider vinegar trick but, I don't think getting rid of adult gnats is gonna change much when harvest rolls in a few weeks.
The trichomes are already 50% cloudy, 10% amber and 40% clear, there's not much I can do about gnats at this point.
The mineral oil already fixed the problem temporarily anyway.

I'll include the 3 og biowar packs into my routine next time to make sure I don't have to deal with this anymore tho.

 

[Seamaiden]

I know it's normal for leave to turn yellow and die late in flowering but this is different.
The brown stuff I showed appears all over my plant, it's even killing tiny bud leave.

This thing is ruining the bag appeal of my bud and that's what bothers me the most.

What brown stuff? Sorry, I just can't see what you're talking about, just those mains.

 

[Bulldog11]

Scope the rust marks. If it crawls then your screwed.

 

[MrBlackThumb]

Here's a picture of a dead bud leaf I found at the top of the main cola.
Just to give you an idea, back when I started the thread, only 2 leave were like this.
Now, there are 6.

 

[Seamaiden]

Looks burned from overfeeding, off the toppa mah.

 

[MrBlackThumb]

Looks burned from overfeeding, off the toppa mah.

That's probably it.
I've looked around for similar issues and the same answer always comes up : overfeeding + heat burn.
I guess I'll lay off the nutes and water with molasses until harvest.

Hopefully my next round will go smoother.
I ordered an EC + pH meter, cal/mag, 3x 8oz bottles of og biowar and some canna coco.
My overfeeding and pH fucking up days are finally coming to an end.