My veg looks like it’s suffering from... everything. Discoloration, stunted growth

Here are the details:

Room: 160 sq ft. Indoor. Temp set to 77 degrees Fahrenheit. Humidity set to 64%. CO2 at 1000.
Lights: 6 gavitas at 500 watts for total of 3000 watts
Medium: botanicare cocogro coir fiber in 5 gallon smart pots.
Water: RO in 50 gal res
Nutes: GH Cocotek grow a and b. Using Potassium silicate for ph up. Cal-mag occasionally.


The plants looked great in the beginning but once they were about 6 weeks old I started seeing red flags. Weird coloration, yellowing leaves, stunted new growth, and droopiness. Checked runoff and it was crazy high, like 2500-3000 ppm. I thought something was getting locked out, so I flushed half the room with 6 ph water at 600 ppm water (300 ppm of base nutes and 300 ppm calmag). Now 2 weeks later nothing has changed except for it maybe getting worse. A couple of plants have started getting very yellow with lots of leaves starting to brown/curl and die. There’s no noticeable difference between those that were flushed and those that weren’t.

Any advice would be greatly appreciated. I’m at my wit’s end!

sounds/looks like a media pH issue...

Potassium silicate is a lousy pH up. Ignore the fanboys pushing it for use this way with cannabis. Go get a real pH up. I use GH powdered up, but your plants could probably use a potassium break for a minute. Branches break off easily?

Root rot will also keep them stalled. Overfeeding and incorrect pH can/will damage roots and stall growth. What's yer ppm/pH? 3k watts, over 160sqft is less than 20wpsqt, so unless you're running about 400ppm or less... massive deficiency issues from overfeeding and root problems. Regular feed strengths will burn the shit out of roots at those low lighting levels.

Use potato test to check for Root Aphids. Good luck. -granger

I don't know shit about hydro, but at first glance 64% seems a bit high for humidity. May not be the sole problem but could be a contributing factor.

Granger2 said:

Use potato test to check for Root Aphids. Good luck. -granger

Click to expand...

Aphids was going to be my next suggestion. Good looking out, granger.

Douglas.Curtis said:

Potassium silicate is a lousy pH up. Ignore the fanboys pushing it for use this way with cannabis. Go get a real pH up. I use GH powdered up, but your plants could probably use a potassium break for a minute. Branches break off easily?

Root rot will also keep them stalled. Overfeeding and incorrect pH can/will damage roots and stall growth. What's yer ppm/pH? 3k watts, over 160sqft is less than 20wpsqt, so unless you're running about 400ppm or less... massive deficiency issues from overfeeding and root problems. Regular feed strengths will burn the shit out of roots at those low lighting levels.

Click to expand...

Thanks so much for the input. I’m currently feeding at 300-400 ppm of base nutes and 100-200 ppm cal mag. Ph is 5.8-6.

Title sort of reminds me of this thread: https://www.icmag.com/ic/showthread.php?t=224050
That one is hilarious