I’ve been dealing with a problem for almost a week now with this plant. It is nearly 10 weeks old, and problems started right at 9 weeks old. It was veged for 5 weeks, and is now almost 5 weeks into bloom.
I’m usually one to help answer sick plant problems, and while I can’t rule out a calcium problem, I really think there is something else going on. Why? Because it’s unlike any calcium problem I’ve ever seen, and I amend my organic soil with plenty of dolomite lime and have never seen anything like this before.
About 1 week ago, I found 1 or 2 leaves that looked like the below images. Now, 5 days later the numbers are increasing.
These brown spots on the leaves are completely dry…that part of the leaf is cripsy.
They appear on the very top of the plant as well as the very bottom, and everywhere in between.
Under magnification, there are no signs of pests anywhere, even the underside of the leaves.
I’m hoping it’s not septoria again. What’s your take?
Here’s what I took off of her today, more than any in the last 5 days since it started. Note that she is currently in senescence with reddish interveinal coloring as is typical of this strain. But these blotches of dried up brown spots, on the edges, in the middle, from top to bottom of the plant have me very worried.
She gets plenty of water, and she drinks a lot everyday. Temperature hovers around 79-80F. RH is 51-52 = VPD around 1.1-1.2 kPa.
I’m not sure about that, as it doesn’t seem to be mobile. Symptoms occur on every part of the plant in random locations. Additionally, there is no interveinal chlorosis, or any pattern to the spots. Some circles in the middle of leaves, some on the edges, etc.
@George The above image shows clear signs of interveinal chlorosis, and refers to lower/middle only.
I’m thinking your soil is off. Possible pH problems but the brown spots cover large parts of the leaves and not just between the veins. Those spots seem like maybe fungus? Reminds me of tomato blight. Do you spray anything’s on them? Humidity higher than normal?
That is the most likely answer, given what I’ve seen of pathogens while growing before. I just never saw one that shows itself after completely drying out in less than 24 hours.
Given the mobility of phosphorus from the roots, I find it hard to believe, but I’m certainly not dismissing it. I’ll amend with some bone meal or something today, as much as I usually shy away from animal-derived inputs.
I’m guessing your mix is a little off. The leaf pics might be P deficiency. I don’t know, but it looks out of balance. A better closer pic of the whole plant might help.
I just gave her a drench of basalt, green sand, gypsum, and bone meal. I do think it is a pathogen though. It’s hard to tell if this is a phosphorus issue, as this is a red variety, and the sprouted seed had a purple stem from the beginning, grown in inert media in a starter pot, along with every petiole thereafter.
I’ll also apply more endo-myco species tomorrow to aid in converting the insolubles.
If it is phosphorus, I will see an improvement within a few days to a week, or at least a slow down from the near exponential uptick I’ve been seeing over the last 5 days since it started.
If not, I’ll have to send in a sample or borrow some lab equipment again. I’m not harvesting any pathogenic cannabis for sure.
Do you have any other plants in the same tent? And if so, do any of them show the same signs? I agree with you that the speed of this seems odd for a pathogen.
I’m saying that partially because I’ve had a couple of my own plants showing similar spots occasionally so I do not want to find out that this is from a fungus. My case seems to be a combination of pH, heat, and excess humidity.
Also, what source of water are you using? I know you said the water is pH’d, so I’d rule out pH fluctuations for now. But I do wonder if the water is too purified to have a good exchange with the nutrients in the soil. Aka maybe the CEC of the water is too low or non-existent. If so, then this could be a lockout partially induced from the water being unable to transport enough nutrients to the plant. But that’s a total guess on my part, not a real theory.
No I don’t – this is the only plant growing in any of my 3 tents right now.
About a month ago, another tent had septoria which looked quite different. It very well could have spread and exhibited itself differently. I’m not ruling anything out just yet.
My humidity is lower than usual, at around 51-52 RH, with temperatures compensated to have an adequate VPD.
I use a combination of R/O (runoff from my industrial dehumidifier) amended with micronutrients using basalt rock dust and such. And I also will use tap water on off days, left overnight to de-gas (our municipality uses chlorine, not chloramines).
My routine or my soil recipe hasn’t changed in many grows. So this is a stumper.
Yeah, stumper is right. This one seems to like it’s presenting itself strangely. Whatever it is.
Just a thought - could the plant be N deficient right now? All of the pics of spotty leaves also show they are all a very light shade of green. Almost the color of new growth for all of them. So maybe those leaves are all yellowing in addition to the spots.
Crunchy spots, right? That’s what I had too. In my case I started feeding with more N as well as Epsom salts for Mag (with a Sulfur bonus). Doing that (and also an extra bit of calcium, sometimes) is what seemed to help my plants, and the spots stopped appearing.
That would be hard to believe as nitrogen is a mobile nutrient and this occurs on the top as well as the bottom and everywhere in between. A nitrogen deficiency is the easiest to identify in my opinion. Slow change to a yellow color without desiccation, until eventually it rots and goes necrotic. Very slow process, and clear path of progression from the bottom upwards.
In my case, the leaves look a nice healthy dark shade of green one day, and then the next, brown crunchy spots. Not isolated to one location. Just random leaves anywhere on the plant, old or new. Even top cola leaves.
Actually, yes. It was in a SoG of 20 solo cups, with a completely different soil mix, caused by frequent waterings required in such a small container, in addition to the different soil I tried.
It very well could have spread, but it presented itself much differently.
In addition to drenching with a phosphorus-rich and micro-nutrient bloom tea as stated above, I will also be spraying down the plant with a concoction I refined to deter mold growth. It mainly consists of fermented citric acid and lactose, dilluted in water, and is safe to apply up to harvest. It is what I have used in the past to combat PWM when growing in a crowded tent, and worked wonders.
I’ll continue to throw all my tricks at it, and hope for the best. I’ll keep this thread updated with the results.
It’s quite okay if this plant doesn’t make it. It’s the last flowering plant I have until I can start my breeding project (I need another tent free to begin). I have enough flower in jars to last me a year or longer, so it’s really no sweat.
so I do not want to find out that this is from a fungus. My case seems to be a combination of pH, heat, and excess humidity.
Aka maybe the CEC of the water is too low or non-existent. If so, then this could be a lockout partially induced from the water being unable to transport enough nutrients to the plant. But that’s a total guess on my part, not a real theory.