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My cannabis leaves have weird spots on them

S

Scott1245

New member
Hi yes I’m having a little problem with my plants and I don’t know what to do I went to sleep last night and woke up and my plants leaves now have a bunch of round rust spots on them here is a picture please any advice I watered with cal-Meg and ph water at 6.5 and two days later this happened
 

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I calibrate my pH pen Every time I use my PH pen and i have never dropped it i have two ph pens and I know no matter what one will be off a little more than the other but for the most part they read dang near the same you know so I am just trying to figure it out cuz It was on a lot of leaves but not to bad and my other plants get the same ph water I make up and it’s doing great unless I am doing something wrong when I calibrate my ph pens and my last 5 grows went great I mean a little problem here and there but nothing like this just looking for a little advice cuz I thought the same thing ph could be off one pen says 6.5 and my other pen says 6.3 and this one is a cheap one the 6.5 is a not so cheap one but i can’t understand could both the ph pens be jacked up I’m stumped and really need some help
 
Certainly need more info!
Each plant is an individual, even in the same seed pack.
OK the PH going in is 6.5, but, what is the PH of the runoff? What are the roots in? What is in that to buffer the PH?
 
Be sure and check the box for red stems as one of your symptoms if you use GWE's plant problem link. Grow info such as what grow media (hydro, soil, coco) would help us help you. The red stems and yellowing between veins suggests magnesium deficiency. If you're in coco and not soil, you'll want the pH between 5.8 and 6.2 in veg and only a bit higher in flower.
 
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Are you checking run off pH? Just because the water going in is right doesn’t mean the pH at the roots is right, especially if you are using Fox Farm soil which tends to go acidic.
 
I’m running a viparspectra P1000 in a 2ft x 2ft 48in tent I’m using Natures living super soil I’m growing to photo plants one White Widow and a Grape Ape from Growers Choice seeds they are in weeks 7 still no sex yet and I can honestly say I don’t remember which one is which do to the fact I took the strips I had them labeled on out to flush them and now I can’t remember which one is what so yeah I’m having a hard time like it’s weird I grow some dank ass autoflowers like 8 grows or so completed and two photo grows decent harvest but these are really just not doing well my environment is good two fans duct fan carbon filter temperature is always between 68 and 76 humidity is at 58and 45 I don’t add any other nutrients to my plants just a little cal-Meg and recharge and in flower I use flower file but one plant looks sad and the other one is doing well just can’t figure it out
 
calcium.... what type of water are you using...some tap water makes it difficult to dial in nutes..I would flush them with ph water. in the mean time i would also mix up a diluted spray and mist them while your flush dries out.
 
Tracking down issues can be discouraging and you can get overwhelmed with good intentions. I will add mine now as it doesn't get much attention. I had several successful grows under my belt when I ran into issues that looked similar to yours. I suffered through grows with the same recurring issue and nothing I did worked. I stumbled across an article and photos of cal/mag toxicity. I finally figured out my city water was hard and already had enough cal/mag so by adding more I was poisoning my girls. Not saying that's what you have going on but check the hardness of your water source. I haven't had any issues since I stopped adding cal/mag.
 
Humm I was just wondering about the huge amount of cal mag...I have not grown inside since we moved, but I did notice when mixing seed strength solution the other day, it required twice the amount of water to bring the ec down...That made me wonder if the plants are even getting the required amount of nutes. I have looked at ro system and have one on my wish list.
 
Just a quick note from an organic grower (which it sounds like you are...partly). If you're growing organic (without synthetic nutes/supplements), it can be very detrimental to add things like cal/mag or other supplements. When you're going for an organic grow, you take care of the soil biome. This means that all you do is take care of the fungi and bacteria which in turn take care of the soil which then takes care of the plant. Oftentimes, synthetic additions can kill off those beneficial microbes which cause a deficiency or toxicity.

It also sounds like you may be pH-ing your water. With organic grows, that can be detrimental for the same reason - pH up and down have chemicals in them that damage the soil biome which begins a domino effect ending in the plant showing symptoms. When growing organic, the microbes manage the pH for you. Afterall, when was the last time you saw a farmer out pH-ing raindrops as they fell from the sky? If you do end up having to pH your water, use organic methods - baking soda for pH up, and lemon juice or white vinegar for pH down.

You mentioned that you've done multiple autoflowers in the same setup and they have done well. With autoflowers, they're usually done in a total of a few months whereas photos tend to take longer. This means that photos have more opportunity for things to go a little off-kilter meaning that deficiencies/toxicities have more time to show themselves or at least to progress far enough to show symptoms.

They don't look like they're in the flowering stage yet, so I would let them be for a little bit. Make sure you're not overwatering (VERY EASY in organic soil!), make sure temp/humidity are in check, and see if that stops the problem from progressing. Note that the brown spots will not turn green again, so the goal is to stop the progression, not turn brown back to green. It may take a week or longer, so be patient. The good thing is that if you are still in veg stage, you can delay the flip for as long as you need to.

Also, if you are going to proceed assuming that there is a deficiency, try using epsom salt in your next watering or as a foliar spray. See https://www.growweedeasy.com/wp-content/uploads/2010/04/magnesium-info-marijuana.jpg

Good luck!
 
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