Red on yellowing leaves

Hey folks! I’ve noticed that three of my clones have started developing yellow leaves with a pinkish red coloring on them. I’ve never seen this before. Any idea what could be causing it? The closest I could find on grow weed easy was it could be a Molybdenum deficiency, but my runoff pH is fine.

Medium: Soil (one plant is in FFOF, the others are a local 420 blend)
pH runoff: 6.1-6.3
TDS runoff: 150-300
Nute line: FF Dirty Dozen
Lighting: Vivosun 300W equiv LED (18/6 photoperiod)
Strains: LSD and Chocolope (both clones of my own making)

@aspir2005 Could that be part of the strain? @Zee does oldguys plants have a red tinge to them?


That was one of the charts I consulted, but there’s nothing on there about red or pink on leaves that I saw. Interestingly, Molybdenum deficiency according to Grow Weed Easy’s Cannabis Doctor has red/pink leaves as a symptom but it’s not reflected in that chart you shared. However, GWE says that Mb deficiencies are usually caused by pH being too low, rather than a lack of Mb in the soil. But my runoff is between 6.1 and 6.3 for each of the affected plants, so I don’t think that could be it.

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sorry, i was hoping that would help you

I appreciate it!

You have a Potassium def (K).

Potassium helps regulate temperatures in the leaf surface and without it the leaves burn like that.

You should perform a runoff PH and TDS test to determine the residual strength of salts in soil before you supplement, but you will be supplementing. If you are K def, then you are P def as well.


Oh interesting! I wouldn’t have guessed that. My pH is 6.1-6.3 and TDS is 150-300 (ranges because there are 3 plants affected). I think my TDS is a bit low for this stage of growth. The mother plant and initial clones also never had this issue; maybe these second gen clones are a bit more sensitive? There is also necrosis on some of the leaf edges, which is consistent with your diagnosis. So I’ll try increasing P and K nutrients and see if it helps. Thanks @Myfriendis410!

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Indicates soil is depleted: treat like soilless and PH to soil values or about where you are now.

Soil, even depleted tends to buffer nutes a bit so I would do targeted feedings with N, P, K to 1,200 ppm (NACL scale) and keep checking runoff. But plants are hungry.


1200 ppm is what the FF nutrient schedule says I should be feeding at. That number just usually scares me pre-flowering. But like you said, these things look hungry so I may as well try!

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