Would someone tell me what this is caused by

Could someone tell me what causes this? I have a rdwc with 7 5 gal buckets. 600 watt hps, using gh trio, cal mag, silica, and flower fuel for my nutes ppm at 1190… P.h. is at 5.96, I keep it around 5.8. I have 3 fans and the grow room temp with hps on is 82. I flipped to 12/12 on 9/22. This is my first grow as well. I’m running a scrog due to height limitations. My light is 18 inches away from plants and I’ve held my hand under light, so they’re not getting too hot.


High intensity lights can make plants extra calcium hungry: I’d up the dose of cal mag and look to new growth for signs of improvement. An overall shot in white light of affected plant would be helpful.

What is water temp? How far below net pots is liquid? 1,190 ppm is a touch high but many plants can tolerate it. I’d recommend shooting for 900 ppm or so.


Temp is at 74 water is 3" below bottom of net pot.


Calcium yup, @Myfriendis410 has you covered.


Thank ya’ll…


Definitely looks calcium deficiency. After adding more, if it doesn’t seem to be helping fast enough, you can bump you’re pH to 6.2 for a bit until it recovers.

At 6.2 you’re plant can take in a lot more calcium. 6.5 is the extreme option but I wouldn’t take that risk unless you’re in big trouble.

This is strictly hydroponics— soil it is different.


lol. yessir, thank you.