PH, Nutes, or did my girls catch their first STD (fungus)?

Any suggestions greatly appreciated. Was transitioning to flower so they received an equal dose of Micro, Grow, and Bloom this week. I thought I had either a ph issue or had locked out some nutes due to spots/tacoing. Had extreme humidity for a few days which is making me question mildew as the culprit. Affected old & new growth, top to bottom but random leaves. Some of the fans were 10"+ so it was definitely crowded.

Trimmed the bad leaves, applied neem based fungicide spray and really curious as to what the experts think?

Purple Haze & White Widow
5.78-6.02 PH
RO Water
GH Flora, Cal Mag, Armour Si, H202
842 PPM and steady dropping, 1.62G per day consumption
Air 70-78F Day, 66-72F Night
Water Res 66-69F
Humidity shot up to 80 & 90% this week but back down to 65-70%
600w MH, 320w LEDs 18/6
7 Weeks from Seed in Transition to Flower

1 Like

Welcome. I would start by getting a run off and check . PH numbers also check ppm I don’t see any mildew problems in the picture. I always likes to verify my pH meter. In a good clean bottle of 7 pH solution. Good luck.

1 Like

He’s in hydro.

It looks like you had a PH departure at some point and it’s showing now. If your phosphorus levels were low the plant can’t regulate temps well and you can get some burning. It has the look of a cal mag def but I don’t think you have that. Overall good color so it may have been transient.

1 Like

Good catch, my bad. Thanks.


I was thinking phosphorous but i had nothing on the middle of the leaves and a few resembled rust fungi or mildew. Thanks so much for the feedback

1 Like

For rdwc stay 5.5 to 5.9 so you dont get lockout.

Do you have a separate reservoir ? If so check filter in pump is clean. No water flow = no new nutes to plant.

Keep water temp under 70f if possible. This causes a lot of issues including root rot. If boardering 70 use hydroguard. Actually best to just use it to improve grow environment.
Watch new growth as the old growth wont show improvement.
If ph is fluctuating down a lot drain system and refill with new water and nutrients. ( be sure to bubble out chlorine 30min for 5 gal before use. Or sit in pail 24hrs before use)