Help with Yellowing Leaves - Nitrogen Deficiency?

Hi all,

Over the last week and a half, my current Chemdog grow is getting yellowing / dying leaves at the bottom of the plant. Is this the sign of a nitrogen deficiency? I'm growing organically in a mix of super soil (Kind soil at bottom of pot) and coco coir (top half of pot).

If this is a nitrogen deficiency, what's the best way to address the problem with an organic solution - I've heard coffee grounds but that apparently takes a while to be effective. Any other recommendations?

I dont have any experience with organics, but it doesn't appear to be nitrogen related. Looks more like an environmental thing. Leaves appear puffy, suggesting watering too often as one possible culprit. Are temps/humidity in check? Air circulation? The plant in the top left has that one yellow leaf on one leaf quite high up, doesn't seem to be nutrient related.

Temps and humidity are good - mid 70's F; RH about 50%. In my veg tent I have passive intake, and a 4" exhaust. I've actually been explicitly trying to stretch out time between watering - I was doing every 4 days; last watering I waited 5 days and the problem seemed much more pronounced this last watering. I haven't been in the veg tent much lately as I was harvesting the last couple of weeks in flower tent, but really all I'm doing right now is watering.

Im not too sure, but nitrogen deficiency would be a more uniform yellowing of the bottom of the plant, and when the leaves yellow, they yellow uniformly as well, not between the veins or from the edges in like yours are. It's possible that they just don't get enough light and the plant is shedding them, but usually that would only happen to me once in flower. Keep an eye on it to see if it moves up.

Blitz35 said:

Im not too sure, but nitrogen deficiency would be a more uniform yellowing of the bottom of the plant, and when the leaves yellow, they yellow uniformly as well, not between the veins or from the edges in like yours are. It's possible that they just don't get enough light and the plant is shedding them, but usually that would only happen to me once in flower. Keep an eye on it to see if it moves up.

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After posting my previous response, I did have one environmental issue that was starting to cause other problems - I wasn't paying enough attention while harvesting my other grow, and let the LED get about 4" closer to the plants than I should have - the larger plants were starting to exhibit twisting / tacoing at the tops. I moved the lights up, removed the yellowest / driest leaves from the bottom of the plant, and have kept an eye on the other yellow leaves. Things seem to have stabilized / started improving - I guess not a nut issue, but still not sure what was causing the yellowing. In looking back at my earlier pictures, I can see some signs of the bottom leaves becoming a paler green - maybe a precursor to the yellowing?

I started transplanting today and moved the grow into the larger tent.

Forgot to mention - one other possible issue is my local tap water. I haven't been bothering with checking my water pH, but recently read the water report from my water district and saw that they raise the pH to 8.2 to help with combatting pipe corrosion. I ran a test of my water today, and sure enough it was over 8 - I used the same water in my last grow, seemingly with no issues, but maybe that's somehow contributing??

Besides not getting light, the only other times this happened to me, was when i put my girl in the closet with some lights and closed the doors..had to hide her due to repairs being done, and 2 days later i noticed some yellowing on a plant that was 100% perfectly green when put in there. I didnt know it then, but when it happened the 2nd time months later to another girl that i was putting in the closet just for overnights to give her 12/12 darkness, it was really hot in the room for 2 nights, and in the closet maybe even hotter and no air movement, the next day when taking her out, at least four random leaves yellowed more than halfway on again, a plant that was completely green prior to going in..so for me, excess heat with no air movement caused it.

Cali Cajun said:

Forgot to mention - one other possible issue is my local tap water. I haven't been bothering with checking my water pH, but recently read the water report from my water district and saw that they raise the pH to 8.2 to help with combatting pipe corrosion. I ran a test of my water today, and sure enough it was over 8 - I used the same water in my last grow, seemingly with no issues, but maybe that's somehow contributing??

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Absolutely, i assumed you were ph'ing the water. Tap water will most always be closer to 8 for that reason, to avoid corrosion. I wouldn't think you have a ph issue as again, that would affect multiple leaves, not just 1.

That makes sense, and when I was harvesting heat was a huge issue - plus I hadn't set a timer up in the veg tent; previous grow I vegged for 18 hours a day; and during the heat I had the light on 24 hours. Things seem to have stabilized and I have active intake and exhaust in the other tent I just moved them to, so crossing fingers...thanks for stopping me from adding nutes!!

Blitz35 said:

Absolutely, i assumed you were ph'ing the water. Tap water will most always be closer to 8 for that reason, to avoid corrosion. I wouldn't think you have a ph issue as again, that would affect multiple leaves, not just 1.

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I read mixed things as to whether checking pH was required for organic soil grows, and head was swimming with all the information I was trying to absorb. A lot to learn but I'm having fun - thanks for taking time to help out!

Cali Cajun said:

I read mixed things as to whether checking pH was required for organic soil grows, and head was swimming with all the information I was trying to absorb. A lot to learn but I'm having fun - thanks for taking time to help out!

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I never grew in a completely organic matter, but i read mixed things too about ph'ing in organics..perhaps that's why you were able to get away with 8.0 water for so long? I would still feel better giving them 6.5ish lol
Ya heat seems to be an issue if it stands still, maybe the extra humidity too. Under my lights, even now, its 30 celsius at the canopy plus whatever it is with the 50% humidity and all plants are doing great, but they are by an open patio door and fan blowing on them all day, but in the closet, overnight, hot standstill air, and it went yellow overnight. Good luck the rest of the way!

Blitz35 said:

I never grew in a completely organic matter, but i read mixed things too about ph'ing in organics..perhaps that's why you were able to get away with 8.0 water for so long? I would still feel better giving them 6.5ish lol
Ya heat seems to be an issue if it stands still, maybe the extra humidity too. Under my lights, even now, its 30 celsius at the canopy plus whatever it is with the 50% humidity and all plants are doing great, but they are by an open patio door and fan blowing on them all day, but in the closet, overnight, hot standstill air, and it went yellow overnight. Good luck the rest of the way!

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Thanks Blitz! Ya; I bought the pH down today - will start using that on the next watering.

Whatever the issue was, it seems to have taken care of itself between moving to the new tent and adjusting the water pH.