Dwc leaf diagnosis needed

Fitzera

Well-known member

• Feb 22, 2017

• #1

Hey all,

New here and first time hydro. The setup is as follows:

Dual pail dwc (changed out weekly)
900w g8led (450w actual) 35" from plants
600w hps added for flowering
Gorilla grow tent 5x5
Advanced nutrients sensi ab ph perfect and hobby package
Half ro half tap water
Starting ppm: 170
1/4 strength nutes ppm: 240
Average temp: 26
Average humidity: 55
Average water temp: 23 (higher than I would like)
Feminized auto seeds

Everything has been going great until today. Brown spots, leaves curling upwards, dark waxy color on one of the early miss plants. I can't match it to any of the pictures I've been searching. Any ideas?

 

thinkin

Member

• Feb 23, 2017

• #2

post to infirmary

post to infirmary

Should post these questions in the Infirmary.

Anyways..

Even given "PH" perfect mix, have you checked the ph?
Air pump working?

IMHO given the complete nute mixes these days, shouldn't be any deficiencies. Thus, I always suspect PH or air to root issues.


suspect the PH might be low.
I always try to keep PH 5.5-5.8

My go to post for plant issues:
https://www.icmag.com/ic/showthread.php?t=46474

 

Douglas.Curtis

Autistic Diplomat in Training

• Feb 23, 2017

• #3

Ph and/or salts spotting.

You'll get better (more predictable) results with using straight r/o water. Leave the tap for your veggie garden. The most commonly needed (varies by pheno/strain) element, for cannabis, is magnesium which is easily supplied with epsom salts (magnesium sulfate). You'll also see an increase in terpene production with the additional sulfur.

 

Fitzera

Well-known member

• Feb 23, 2017

• #4

Thank you, I was last leaning towards a root issue as it looks like a symptom of over watering in soil. Also the ph did climb up to 6.4. I will be doubling the air to each bucket and bringing the ph down.

 

Douglas.Curtis

Autistic Diplomat in Training

• Feb 24, 2017

• #5

Yep, max pH in any roots-in hydro is around 5.8. Spotting usually comes from too rapid of a pH change or multiple pH fluctuations. The slow rise of pH from plants eating nutes from the solution will not cause this.

Check your pH before and after doubling your air... if it starts to go up you're pumping too much air through. CO2 in the air raises the pH through the creation of carbolic acid.

 

Fitzera

Well-known member

• Feb 24, 2017

• #6

Your input is much appreciated, thank you sir

 

Douglas.Curtis

Autistic Diplomat in Training

• Feb 24, 2017

• #7

Fitzera said:

Your input is much appreciated, thank you sir

Click to expand...

You're entirely welcome I've run DWC (roots-in hydro) for nearly 15 years and love it. Once you understand the environment it needs and how to maintain the reservoir, it really becomes ridiculously easy to run.