Yellow or rust like dots on leaves

This plant is in a DWC bubble bucket and I'm been using the Lucas Formula: 8ml FloraMicro per gallon, 16ml FloraBloom per gallon. The PH is always close to 5.8, filtered RO water and everything.


These yellow dots start appearing and gradually consume the whole leaf.


The plant as a whole is still growing like mad and it's roots are going crazy in the bucket.


Any idea what's wrong?

Has to be Ph bro, get it to 5.8.

I'm still learning myself but, what I have seen all say is that you need to add a Cal-Mag supplement to RO water because it is removed in the process. 5.8 ph with DWC sounds right to me. But I run organic soil so, not real sure. Google "Leaf Deficiantcy Chart", "Cannabis PH chart" and save them to your files. Good luck.

Could me manganese def - have your bloom nutes got magnesium in?

too much magnesium can lock out manganese at that ph range

Shaker1 said:

I'm still learning myself but, what I have seen all say is that you need to add a Cal-Mag supplement to RO water because it is removed in the process. 5.8 ph with DWC sounds right to me. But I run organic soil so, not real sure. Google "Leaf Deficiantcy Chart", "Cannabis PH chart" and save them to your files. Good luck.

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I agree, first thing I thought of is cal/mag

I would agree with Magnesium deficient. Not only the spots, but the curling of the margins is a sign.

My PH is low 5's right now. I was looking at those charts and Magnesium isn't absorbed well with low PH. I'm going to raise the PH to get it closer to 5.8. That must be the cause thanks!

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If you have a deficiency/lock out caused by low ph you need to flush first. I would flush with r/o water until your runoff comes up to where you want It and then give a light feeding.