Can any identify what this issue is?
- Thread starter rznball
- Start date
Running 6/9 gh micro/bloom with silica and some rapid start. Room is 11x25 with 10 750w DE lights currently set at 75%. Lights are about 4’ at least from canopy. 4 phenos same strain, only pheno with the issue is this one. Temps and humidity are good. Ph was a little high last week at 5.9 and I have it around 5.5-5.6 this week. Plants are on a drip that’s being turned on as needed right now. Unlikely to be nitrogen since it’s in the new growth. Here’s a couple more pictures.
Mike Litoris
Member
Looks like Mg def
It looks like the Textbook photo of early stages of a K deficiency.
Seems your ph is actually too low. Coco optimal ph is 6.0-6.2.
Get the ph squared away and flush it real good the add back some nutrients and some epsom salt, she should bounce back fine.
Get the ph squared away and flush it real good the add back some nutrients and some epsom salt, she should bounce back fine.
Interesting. I had thought Zinc. I have only seen K express itself as burnt edges and in books as a white leaf. As a mobile element K signs should start from the bottom. Zinc has that striking green edges and stripes between the veins. Seen on newer growth as it's not mobile. It likes that low pH though and is rarely deficient.
You say textbook and zinc is rare. I just don't feel convinced though. Can you offer any more insight?
It looks very much like magnesium deficiency/lockout. Check this out 5 seconds in:
https://www.youtube.com/watch?v=lvg-VzGHfQU&t=5
https://www.growweedeasy.com/wp-content/uploads/2010/10/marijuana-magnesium-deficiency-sm.jpg
https://www.growweedeasy.com/cannabis-plant-problems/magnesium-deficiency
https://www.youtube.com/watch?v=lvg-VzGHfQU&t=5
https://www.growweedeasy.com/wp-content/uploads/2010/10/marijuana-magnesium-deficiency-sm.jpg
https://www.growweedeasy.com/cannabis-plant-problems/magnesium-deficiency
The artists impression sure looks close.
This is often used as a zinc example
Zinc is so unlikely though, if the feed is correct.
Mg, Like K, is mobile and should start lower in the plant. Mg is often confused with Iron though which would show in the newer growth. It's a tough call but that is just so brightly coloured.
GH feeds.. I don't have a clue
Edit: The plants looks like it's in veg but is getting Flower food and rapid start. A boost that sounds like it's P based. That would be a lot of P for a vegging plants and P pushes out zinc. It's about the only way to get zinc problems
This is archetypical magnesium deficiency - at the start of flowering. The leaves are dark green/blueish. The yellow tips are telling. And this is a mobile nutrient deficiency:
1. The tops are not affected (which happens with a non-mobile nutrient deficiency)
2. The lower leaves are more affected than the set of leaves directly above it.
That limits it to N, P, K and Mg.
The image is about 5 seconds into the video.
https://www.youtube.com/watch?v=lvg-VzGHfQU
Magnesium Deficiency.
I agree that the pH is too high. A high pH will lock out NPK and Mg. For coco coir, the pH should be the same as the medium itself for most of the grow - 6.0.
PH'ing the nutrient solution to 6.0 doesn't challenge the buffering capacity of the coco, so there won't be pH-swings.
1. The tops are not affected (which happens with a non-mobile nutrient deficiency)
2. The lower leaves are more affected than the set of leaves directly above it.
That limits it to N, P, K and Mg.
The image is about 5 seconds into the video.
https://www.youtube.com/watch?v=lvg-VzGHfQU
Magnesium Deficiency.
I agree that the pH is too high. A high pH will lock out NPK and Mg. For coco coir, the pH should be the same as the medium itself for most of the grow - 6.0.
PH'ing the nutrient solution to 6.0 doesn't challenge the buffering capacity of the coco, so there won't be pH-swings.
