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Dirty roots during transfer to bloom.(DWC)

So i have a cultivation in Alaska that has been going a little over a year now. we started out using grow/micro/bloom jungle juice. Now we use connoisseur A & B. Ever since starting connoisseur 48 hours after putting plants into flower and swapping to bloom A & B we get a light/dark brown build up on the roots. It is not slimy and washes right off. Usually only happens once or twice plants push through and everything is fine there on out. we have started using B-52, Piranha,voodoo and it has been persisting long past the 2 spells of dirty roots. We use RO water, deep water culture, ppms rang depending on stage 420-900, ph always kept right about 6, reservoir temps almost always 68-72 degrees F, no circulating systems just air stones and stand alone reservoirs.
we have used connoisseur grow/micro/bloom going into flower with same results of dirty roots. Tried tap water to see if PH perfect wasnt binding to RO water and still same results. We have tried everything but switching the nutrient brand we can think of but is hard to do when we use same solutions at home with city water on smaller scale and it does beautifully.

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This is it coming back for a 5th time. in a day or two im sure it will all be brown.

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Is there any affect to the foliage?

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yeah it will turn light green and got some spotting. Sometimes curling and drying up.

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Sounds like pythium to me. Have you tried using a food grade 29%-34% H2O2 to try to mitigate the issue when it first presents?

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yes we were using sm90 cut back for a little while then started usning it on a regular regiment to end up switching to hydro guard. that seems to be helping but not completely.

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it also doesnt smell and takes affect like clockwork. it never skips a beat other then getting worse from time to time.

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So the Hydroguard is a Bacillus treatment. This is great for long-term management, but right now you need to kill all the spores that are existing in your reservoir. Unfortunately, you also need to kill all the healthy microbial life as well. Use the 29%-34% H2O2 and let it circulate in your reservoir to kill off the pythium spores. Clean all your media as well as any lines and tools that may have come in contact with the infected material. The same hydrogen peroxide can be used for sanitation. After you have used the H202, start using the Hydroguard as maintenance. The problem with using the Hydroguard before the H202 is the H2O2 kills off the Bacillus in the Hydroguard.

My guess is there are still pythium spores hanging out somewhere in your grow environment just waiting to rear up and hurt your plants all over again.

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Hey @mastergrowers, @growopowners, @GrowOpEmployees

Take a gander at this issue that our friend @bg.arcticgreenery has presented us. I say pythium, but I have been wrong before. Any thoughts on this one?

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I spoke with a grower colleague and he suspects that if it’s not slimy, the kelp in the B52 is causing a deposit to build up. Remember, both the Liquid Karma and the B52 have kelp in them. You may just be experiencing a kelp build up which could cause the discoloration but not have an overtly phyto-toxic effect.

My colleague also suggested you switch to Aqua Flakes from H&G, but he’s very loyal to that product. Haha good luck!

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This whole conversation made realize two things.

  1. My grow vocab is horrible…literally googling those terms to try and better understand what you were talking about.
  2. The feet of the fungus gnat are frequently a vector for pythium transmission. Never thought I would know that. HAHAHA

Good luck on your grow!

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This is how we all learn, @RayWearCC. I assure you I was not born knowing about pythium…sometimes I still have to check on the correct spelling on some of these afflictions! We are here to learn and grow as a community!

The feet of fungus gnats are frequent vectors! Thanks for pointing that out!

@bg.arcticgreenery, do you have fungus gnats floating about the grow?

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Kelp is tricky these days due to our ocean’s pollution. Kelp holds on to toxins cleaning the waters of salty ocean’s. I use it very sparingly! Acadian brand is the one i do use. Very small amounts.

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I did not see any reference to Fungus Gnats, but Ray is correct here. It has also been documented that FG can carry pythium spores in their gut and transmit it while feeding on roots

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Nemstodes from a refrigerated store are key. Rogalia absolutely works as well. Just make sure it plays well with other products you may be using. From my experience, it works well with most other fungicides( all OMRI- approved for canna production is key) would not use it if you use MET-52-

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Here is a nice primer on Common Root Rot in Cannabis

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Good to see you back online @ethan! We missed you and hope you are doing ok. :slight_smile:

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Pythium can be very difficult to cure in DWC. There are multiple strains of pythium that can lay dormant year to year and resurface from dirty plastic or surfaces even when you may have thought it was irradicated. Zoospores can even swim in irrigation water, so cleanliness in a DWC setup is critical. You have to get all organic material off your plastic, then try an acid cleaner like “green clean” from biosafe as part of a 3 or 4 step sanitation process - rinse, soap, rinse, sanitize.

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The core issue is a hydroponic system that sounds like it is recycling water.

Fungus gnats are one common vector. But, so is unfiltered water. Nematodes, from a reliable source are a good practice to control only quiescent sources. The nematode actually eats the spore. Not an effective control on the pathonogenic stage.

We use to have a greater problem in parts of our fields than our greenhouses.

A large midwestern Greenhouse operation used flood floors for a number of crops. They came to the conclusion that cleaning there recycled water was the only way to stay ahead of the problem. They also where forced to use a class of chemical that are not available to the cannabis growers.

I can’t think of an organic control for a systematic pathogen.

I can come up with a list of 100 things to do from a prevention standpoint, but I can not think of a single thing to do post infection, that would qualify as organic.

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Thank you for all the helpful pointers. We will make sure to scrub and sanitize a lot more then usual and take the precautionary measures for pythium just in case. it does sound like it could potentially be the issue or maybe part of the issue as well as the B52.

@Growernick, We have had fungus gnats floating around in the past. As far as i know they are all gone but have seen some come back but not on a large scale like they were when we first got them but with hundreds of reservoirs they could be tucked away somewhere. its just weird because nothing has been slimy like root rot. No odor. Just discoloration like something in the nutes coagulated and stuck to the roots.

@ethan, We currently pump fresh RO water every time we mix nutes and dump the run off.

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