Callling all doctors! Top Cola damaged going spotty yellow, tough and leathery

[Smeghead]

Halp! I'm starting a new thread because things have deteriorated on this 60 day wonder. The top cola leaves are going spotty yellow, tough, leathery and tips are going crispy like it's chop time.

Problem: Continuation of this deficiency or lockout, no diagnosis provided. Still a mystery to all.

Feed: Advance Nutrients PH Perfect Sensibloom A + B


What type of medium; soil or hydro? Hydro

Indoors or outdoors? indoor
What strain? 60 Day Wonder
How old are the plants? 8 weeks old
What type of lights and how many watts? 2x GN MS0006 270w x2
How far from the lights? 8 inches
What, how much and when was it fed? NPK? EC 1.6
What are the temps and humidity in the room? 70-75F
What size pots? 3.5 gallons
Any bugs? Look real close. 3 dead gnats in the rez last change
Any other pertinent info? Link to OP:

https://www.autoflower.org/f90/i-cant-find-deficiency-chart-32802.html

Pics. Leaves are going yellow, tough, leathery and dry with gold spots. Fan leaves are tough and leathery. Some sugar leaves starting to turn yellow with spots on the top cola as well.

SHOULD I DECAPITATE AND DRY/CURE? I had an accident last res change (last Sunday) where I bent the top cola over 90 degrees and things went downhill from there.

 

[A4]

What is the ph of your res? I know AN says you shouldn't need to adjust pH but I am curious what it is fixing it at.

Looking through your other thread Muddy and Waira suggested Cal deficiency. Unfortunately for you, I am in agreement with them. Here is the deal, I haven't done many hydro grows, a handful but not enough to be proficient. I do know that calcium is best taken up at between 6.2-6.5 regardless of hydro or soil. So we start with that. I also know that too much potassium(k) will lock out calcium among other nutrients. You said the plant isn't taking up much nutrients in your thread, that kinda makes me lean towards maybe you have too high an EC which would of course mean that you also have too much K which could be locking out the Ca. Combine that with, my guess, that your res pH is probably below 6 as it normally should be in hydro and you have a perfect storm for Ca problems.

The diagnosis, pretty easy. How to fix it, not so easy. I haven't worked with AN before but if it were me, I would 1) Dump the res, 2) refill with fresh water and only 1/4 recommended nutrients for the age, 2) make a good mixture of Ca in a spray bottle for foliar. I understand everyone says do not foliar during flower, BS, I have done it on every grow for the past year and a half with no problems at all. So, foliar feed spraying mainly the underside of the leaves, that is where the majority will be taken up at. Spray when lights come on, when the room is still cool and the plants petioles are still closed. As the room warms up the petioles will open and begin taking up the Ca mixture. It normally takes about a week to see Ca defiencies stop spreading as Ca is an immobile nutrient so it doesn't move throughout the plant like N would. That being said, you are going to need to focus your foliar feeding on the new growth. That is very important! Spray mainly at the top of the plant and work your way down. That is where the plant needs the most Ca.

Lastly, foliar feed every day at lights on for a week.

 

[Muddy]

What do your roots look like? Are they a nice white color or are they brown? If they are brown you could have some root rot going on which could also be contributing.

 

[Smeghead]

What kind of calcium supplement should I use for the foliar feed? I've already pruned the top cola fan leaves they were yellow and dead already.



It's almost ready to harvest in the next 2 weeks anyway, only the top of the plant is affected unless it starts spreading to the next set of bud sites below the main cola.

 

[A4]

Look for one that gives you a foliar feed mixture rate, that way you know it contains a surfactant. I use Metrop, my guess is you may not be able ti find that one quickly. If you have a hydro store nearby just ask them for a good Ca/Mg supplement for foliar feeding. They should have one in stock. If you are only two weeks away, do your best to stay away from bud sites as you don't want to be smoking the chemical residue and also hit them with a spray of water for a few days after foliar feeding. That should allow the plant to take up any residue and wash the remainder away.

Like Muddy said, it could be root rot but I assumed you would have mentioned that if your roots were slimy or brown.

 

[Smeghead]

It's all going terribly wrong guys.

I harvested the 60 dw 2 weeks earlier than planned to get max yields. It's been drying a week now. Almost time to start cure. It smells of lawn clippings.

This skunk looks bad now with the top cola. I started flush on it for a week and chop down early. Both grows have gone bad.

 

[Smeghead]

More pics. I need help working out the kinks before my next grow and do one of the same strain again

 

[Smeghead]

What do your roots look like? Are they a nice white color or are they brown? If they are brown you could have some root rot going on which could also be contributing.

To answer muddys question the roots are white and crisp. It's on a water chilled and at 20c the whole grow.