Need Help Diagnosing Possible Root Rot Pythium?

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ntrlslctn

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I am new to the site, I completed my first run without any major issues and had good results. Now in my second run with a different strain they were doing even better for first 4 weeks or so but now I am having a particularly difficult issue to resolve and am looking for help.

Plant just completed 7 weeks of veg, though this issue emerged around week 4 and has severely stunted growth in recent weeks. Plants showing exhibiting slow growth, short node intervals, droopy pale leaves show a variety of stress but often wrinkled or blotchy-nutrients being pulled completely from older fan leaves, dark purple stems, some red leaf veins. Young inner growth is darker and lusher.

I believe the issue is related to root rot/pythium. I think I was being lazy about draining water from trays after watering, leaving roots exposed to standing water. I noticed this was causing the normally healthy white roots at the bottom of my pots to appear brown and burnt, and some had a fuzzy gray mold or fungus growing on them. Algae has been appearing in my tray water. My initial response was to spray roots with neem oil, clean and disinfect trays and improve my watering/draining practices. I lowered temp and relative humidity slightly to around 65F and 50% RH. When this didn't do it, I popped the plants out of their pots and noticed almost the entire rootball appeared healthy white and vigorous except the very bottom. I pruned away the nasty bits, disinfected my pots with h202 and repotted. The next two days I watered with h202 at 15ml per gallon. Next day added compost tea. 3 days later I began adding hydroguard at 2 ml/gallon. I am hoping hydro guard will do it but am looking for confirmation of this approach/diagnosis.

A little bit about my setup, 4x8 tent with 6 plants-3 bruce banner and 3 stardawg clones. I use yellow 2.2gallon airpots with coco coir (60% organic coco, organic perlite, 5% guano 5% EWC). I inoculated with great white, endorsement myucchorizal fungi, soluble rot zone beneficial bacteria/mycchorizal fungi. I have added compost tea a few times during establishment. I feed with general organics nutrient line about twice a week with RO water that is naturally at about 7.0-7.3 but I adjust with earth juice to around 5.8-6.4. I go by the GH drops to measure pH, but my Jellas temp-controlled ph meter routinely measures about .5 pH high than I think it is so I wonder about my pH. ppm has been reading single digits like 7 or 9ppm so I don't know if that's right. For the first few weeks my pH was naturally around 6.4 so I wasn't adjusting it, so maybe that's when the issue started? I have two 600W LEDs on 18/6 and temp is usually 72F and RH around 60%. I have two exhale 365 c02 bags and filter my air coming in and have good air circulation.

Interestingly, I have 2 plants-one of each strain- I set aside as mothers in 3.6 gal green airpots with FFOF that I watered and fed about half as much so they didn't see as much moisture. They are much healthier and larger though they may be exhibiting the symptoms to a lesser degree. They are now in a separate room under a spectrum king closet case 400W LED.

I am including photos of affected plant next to a healthy(healthier) mother plant from same clone batch. If the form of the plant looks strange it is because I did a lot of unnecessary LST in anticipation of SCROG that in retrospect feels redundant.

I think this is root rot/pythium based on the symptoms and difficulty in fixing, but maybe it is just a general pH problem? If the hydro guard does not fix it I am out of ideas and will begin to think about taking new clones for my others. Please share any ideas/experiences, as well as any other general input on my setup. I keep a journal so I can offer more info/photos if necessary. Thanks in advance.
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Need help diagnosing possible root rot pythium
Need help diagnosing possible root rot pythium 2
Need help diagnosing possible root rot pythium 3
Need help diagnosing possible root rot pythium 4
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ntrlslctn

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I think you're right, I probably was overcorrecting my pH and it was too low for magnesium and maybe calcium too. I'll flush and get the pH up and feed them, I'll let you know how it goes. Thanks again
 
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ntrlslctn

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I feed around 800 ppm a few times a week, but I think my pH was so low i got cal/mag lockout. I'm having trouble accurately determining pH because my drip test seems to indicate a lower pH than my digital reader, by a margin of about .5 . The instructions on General Organics nutrient products say adjusting pH is not necessary, so I left it alone for the first few weeks but then I got the organic pH down product and began adjusting it down in an attempt to "optimize conditions". When I was adjusting my pH for watering and feeding I would use the drip test to try to get about 6.0, around the lower end of the range for coco, so even if my digital meter said 6.5, I figured my “true” pH would be somewhere in the acceptable 6.0-6.5 range which is on the low side but good for coco as I understand. (Also, by adding the soil-like organics to my medium mix, I may have raised the required pH range for my growing medium).

To illustrate the pH discrepancy, I am including a photo of my water after performing a pH drip test. When compared to the color scale photo from online, I would say my pH is about 6.5. The same sample read 7.2 on my digital meter. Considering the issues I’ve had, I think the drip method readings are more accurate than my digital tester.

Screen Shot 2018 03 15 at 71121 PM
PH color scale


Today I flushed all plants with 6 gallons each of straight RO water, taking pH and ppm of runoff both before and after the flushing. I then fed with the full GO line(Biothrive 4-3-3, CaMg+, BioWeed 0.2-0-0.3, BioRoot 1-1-1) at recommended rates, forgot to test ppm first but a second batch was around 800ppm. I didn’t mess with the pH of my water for flushing or feeding, just used as is. The pH of my RO water consistently tested 4 ppm and pH of 7.2 digitally, around 6.5 by drips.

-pH readings are based on digital meter for consistency.
-Flushing water consistently tested 7.2 pH and 4 ppm.

runoff test results
(before flush / after flush / after feeding)
S1=6.7 pH 118 ppm / 7.1 pH 35 ppm / 5.8 pH 409 ppm
S2=7.3 pH 712 ppm / 7.1 pH 46 ppm / 5.6 pH 472 ppm
S3=7.0 pH 175 ppm / 7.1 pH 26 ppm / 6.0 pH 372 ppm
B1=7.1 pH 164 ppm / 6.9 pH 37 ppm / 5.8 pH 413 ppm
B2=6.6 pH 138 ppm / 7.1 pH 19 ppm / 6.2 pH 232 ppm
B3=6.5 pH 153 ppm / 7.1 pH 24 ppm / 5.5 pH 418 ppm
 
chemistry

chemistry

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Out of all the samples I like the 6.0 best, the 6.5 look to alkaline. Are you feeding until you get run off? Get hold of some control fluid for you PH meter, it's not expensive, then you can sort your PH and have it bang on.
 
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ntrlslctn

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so yeah, what I was missing was that my nutrients were lowering the shit out of my pH, like under 5. I'd been testing my water and not my nutrient mix all along. Apparently general organics are notorious for this kind of thing. Not sure how I missed this one, but lesson learned. Of course I've been wrong before, but this seems to explain everything. Thanks for steering me in the right direction.
 
Enforcer

Enforcer

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Those plants are decent size, and they are in coco/perlite in an air pot. Your medium will dry out very fast. IMO, you should be feeding your solution daily! 800 ppm is ok for this size, but they need it everyday. Water to about 20% run off each time. They will turn around quick.

Also, you want a ph of 5.5-6.1 for coco.
 
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