Need help with diagnostics

This same issue has happened on my last two grows and I have no idea what’s causing it. It starts with these spots showing up on the fan leaves and within a week or two my leaves will all be yellow and dead. Any idea what this is or what’s causing this?

Deelite auto. Growing organically in fox farms ocean Forrest.
Week 5, Only top dressed her once so far, 1/4 cup of Dr. Earth 4-4-4 all purpose.

Watering with 6.4 PH once to twice a week. Tested with a blue lab pen.

Lights are 2x mars hydro ts1000 at 75%, 20 inches, and a 20 hour light cycle.

Humidity has been dropped from 75% to 55-60% for flower. Temperature is holding steady around 76f during the day and 73f at night.

Trying to jump on this as fast as I can as it destroyed my last batch fairly quickly. Thank you for any advice on advance.

Hi @TheAlchemistsPot I am thinking some kind of bug since plants look healthy I don’t think it is some kind of nutrient problem… time to get up close and look her all over in every nook and cranny.

It looks to me like you just had some water splashed onto the leaves.

If you had something looking like this ruin a previous crop, that was probably a fungal infection caused by the fact you’re running your humidity so high. 55-60 is ok for veg, but you want to be in the 40’s for flower. At 75%, unless it is very warm where you live, you might find condensation problems in your home and you should consider checking attics and crawl spaces for mold.

If you find you’re having trouble getting the humidity down into the correct ranges, some defoliation in the lower canopy can get you a few more percent.


Thanks @retiredoldguy I’ve checked the whole plant with a jewelers loupe and don’t see any signs of infestation yet. I had a small problem with fungus gnats in the beginning of my grow (see fly trap in picture above) but it has cleared up after a good nematode soak. I’ll keep checking her for the next few days though to see if I’m missing something. I appreciate the heads up.

I’m thinking @CurrDogg420 may be on to something. I’ll try lowering the humidity in my tent and see what happens. I did also splash some water on my leaves by accident the other day as well so this could also be the cause.

My tent is the only place the humidity is ever that high. If I turn off my humidifier in my tent it rests around 35-40% I do find my temperature spikes well above 80 when I drop the humidity that low however. I really need to find some cooler lights than the ts1000 I think, even with the ballasts moved outside the tent the temps just get too high too fast.

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So for an update: I lowered my humidity to around 40-45 Everything else is still pretty much the same.

However I’m in week 7 from seed and

this issue I’m seeing on my lower to mid fan leaves is getting pretty prominent. Is this a deficiency or over feeding? Could this be watering? I’m only watering every 3-4 days around 70 oz. Could that still be too much? Thanks for the help everyone.

I don’t think it’s a watering problem. You’ve still only given just the one feeding? It does appear to be a little deficient- the upper growth seems a little yellower than the last pic. It’s a bit early I think for that to be happening.

I can’t quite put my finger on exactly what it’s deficient in, it might be several things. I’d want to give it another feeding of some flower fertilizer; higher in P, I use a 4-8-4, Dr Earth has a “flower girl” that’s like 3-9-4. And also I’d want to water it in with something to boost microbial activity- worm tea, fish emulsion, or molasses would be good choices. This will help the correction happen faster.

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