Brown Spots on Leaves, Nutrient or Light Problem?

Second grow, I replaced a blurple with an HLG-120H-54A. Plant is growing much better but I am getting brown spots on the leaves. I have had trouble with heat but it is now staying btw 25-30C.

Now I am getting brown/orange spots on some of the leaves. I thought it might be the light, but the spots aren’t on the top leaves. I have a compact setup, so my light is ~16-18" away from the plant. My light meter registers at around 1000 at the top of the plant.

I assume this is either a light problem or a Nutrient problem? I am using Dr. Earth 2-2-2 fertilizer and watering once a week with it.


Do you measure nute PPM and pH and runoff PPM and pH?

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I ran into the same problem when I added a 2nd light to my space. Too much added intensity at once. I was also told it could be cal/mag deficiency (or both as added light intensity can bring the deficiency to the surface so to speak.

Based on advice, I lowered light intensity and started turning up very slowly over time, and also added a Cal/Mag solution to my nutrients solution.

I’m a newbie doing my first indoor, so wait for others to respond, but this is my thoughts based on the help of, @Covertgrower @dbrn32 @Hellraiser and some others that I can’t think of their tag right now


Dim the fixture too. It’s light burn.

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Okay great! I can’t really raise my light as it’s as high as my tent allows. I will dim it.

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So I dimmed my fixture but the yellowing is spreading. I added a magnesium fertilizer to my regular nutriets. I also think my ph might be high? It’s hovering at 8.

Dimming the fixture definitely helped. As soon as you drop your ph back down, you should be doing a lot better.

Whats a good ppm to be at. I have meter but dont know what I am shooting for.

I think your input PPM will vary a little depending on what line of nutes you use, but if your runoff is significantly higher than your input, it means you’re feeding more than the plant needs. Significantly lower means she wants more. I just switched to Jacks 321 and I think full strength for it is around 800ppm.

You definitely want to get that down. 6.0-6.5 is what most shoot for.