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What deficiency is this?
- Thread starter spandrel
- Start date
CoconutFarmer
Member
Happy new year. How long are they in flower already? If it's in final bloom stage you don't have to worry about 
It looks like calcium deficiency.
This is the photograph that looks most like it. It has both the shotgun pattern to the blotches that go from the vein to the edge of the leaf.
https://www.ilovegrowingmarijuana.c...-deficiency-in-marijuana-plants-2-600x317.jpg
https://www.ilovegrowingmarijuana.com/nutrients-deficiency-calcium/
https://www.marijuana-seeds.nl/blog/calcium-deficiency-in-marijuana
https://www.icmag.com/gallery/data/500/1134manganese-def1.jpg
Too much Ca will push it out. It likes the pH to be on the lower end of the scale if you want to help it. It's a rare deficiency so a good flush to reduce salt levels is more likely to help than trying to actually find some. Though a trace mix of some sort might offer some relief with a foliar application
Or I could be wrong, it's not unheard of
Edit: I had to go away on this one. Stitches pic shows a straight up Mn deficiency. The OP pics are black formations. The Mn has turned to Mn Oxide. Making it unavailable. It's like black spotting with the retreating N like signs that take me to Mn. I had not realised it was an excess problem. It's in the Canna Info Courier leaflet. Their site might offer further insight into this issue.
Cold Wet and a high pH is a combination that would cause this quite easily
Too much Ca will push it out. It likes the pH to be on the lower end of the scale if you want to help it. It's a rare deficiency so a good flush to reduce salt levels is more likely to help than trying to actually find some. Though a trace mix of some sort might offer some relief with a foliar application
Or I could be wrong, it's not unheard of
Edit: I had to go away on this one. Stitches pic shows a straight up Mn deficiency. The OP pics are black formations. The Mn has turned to Mn Oxide. Making it unavailable. It's like black spotting with the retreating N like signs that take me to Mn. I had not realised it was an excess problem. It's in the Canna Info Courier leaflet. Their site might offer further insight into this issue.
Cold Wet and a high pH is a combination that would cause this quite easily
I'm in week 3 of flower it is definitely a concern.
I thought I spotted a calcium deficiency so I doubled the calcium and the deficiency began accelerating quickly.
I did have some unusual conditions, ph was too low because my solution froze solid and controller couldn't pump, also a thermometer was off by 15 degrees and the plants got too cold at night till I figured it out.
I've flushed and changed nutrients and foliar sprayed manganese chelate. I guess I'll know in a few days. Thanks f-e good info on the canna website
I thought I spotted a calcium deficiency so I doubled the calcium and the deficiency began accelerating quickly.
I did have some unusual conditions, ph was too low because my solution froze solid and controller couldn't pump, also a thermometer was off by 15 degrees and the plants got too cold at night till I figured it out.
I've flushed and changed nutrients and foliar sprayed manganese chelate. I guess I'll know in a few days. Thanks f-e good info on the canna website
Other than calcium deficiency, it could also be calcium lockout.
The run-off will tell whether there are too many nutrients in the medium. Calcium is antagonistic to a host of other nutrients which will block it out.
https://cdn.shopify.com/s/files/1/0512/6505/files/SoilTesting_Fig2.jpg?v=1552544085
Thank you it's a RDWC system there isn't any runoff.
The initial effects did look very much like a calcium deficiency. I suspected manganese from internet research but the necrosis on leaf veins didn't seem consistent with a manganese deficiency. I have very low ppm water so I add calcium chelate to my solution, increasing that is what I think let to the manganese deficiency, even if there was a calcium deficiency at first.
The manganese chelate foliar appears to have stopped the deficiency in its tracks.
Love ICMAG thank you
The initial effects did look very much like a calcium deficiency. I suspected manganese from internet research but the necrosis on leaf veins didn't seem consistent with a manganese deficiency. I have very low ppm water so I add calcium chelate to my solution, increasing that is what I think let to the manganese deficiency, even if there was a calcium deficiency at first.
The manganese chelate foliar appears to have stopped the deficiency in its tracks.
Love ICMAG thank you
The solution I used for R/O water, was to put a teapsoon of magnesium lime (Maerl) in a quart of R/O water, let that stand for a day, and then filter/pour off, and mix it 1/4 to 3/4 of more R/O water.
That worked to get rid of magnesium deficiency. There has to be a correct ratio between calcium and magnesium.
I also remember using a Cal/Mag nutrient that smelled like it was made from bonemeal and didn't work at all. So it has to be emphasized that some cal/mag nutrients do not present these nutrients in an absorbable form. Maerl and rock/mineral solutions work.
It can be that some strains need more calcium, or need more calcium at specific stages of their development.
Hello,
I'm using 50ppm tap water. I don't have problems with magnesium deficiency, but calcium needs to be added. Perhaps some water testing would lead to improvements.
Manganese seems to be the culprit I was posting about. Plants are now bulking nicely, fingers crossed.
Love
I'm using 50ppm tap water. I don't have problems with magnesium deficiency, but calcium needs to be added. Perhaps some water testing would lead to improvements.
Manganese seems to be the culprit I was posting about. Plants are now bulking nicely, fingers crossed.
Love
I agree that it is manganese deficiency/lockout.
https://www.zambeza.com/blog-how-to...nganese-deficiency-in-your-cannabis-crop-n153
"New and older, lower leaves will begin to turn yellow."
In my defense, I didn't see the entire plant.
Just from a fan leaf, it looks like a mobile nutrient deficiency.
