Root Rot: Question for the experts

Discussion in 'Sick Plants and Problems' started by paestum, Nov 28, 2022.

  1. Hey there
    So I have an Aerogarden hydroponic system (10l). Planted on October 10th so almost at harvest which is driving me nuts...
    OK- the bad that happened before this. I monitor the water although generally cold a few times it was hot (bad). But I realize there was light that was creeping in through the clear tubes. I thought with three pumps and three stones directly under the each of three plants in the bowl I would be fine... alas... Lessons learned.
    Until about a week ago the plants were doing great. Then I noticed the leaves start to droop. I knew what was coming and acted quickly.
    I immediately emptied and sterilized the tank with bleach, boiled the stones with vinegar, then again with bleach for 15 minutes... then cut the dead roots off and stuck the plants for several hours in diluted hydrogen peroxide and for several more hours in Hydroguard.
    Yet 24 hours later, despite all of that I still can smell a little mold when I smell the roots. The water isn't smelly, it's clear and there is very little debris in it. The roots don't look bad and are developed enough/substantial enough that I am holding onto some hope. The plants however are clearly stressed.
    Right now I have them running with a larger amount of Hydroguard than recommended... recommended amount is 2ml per liter, I put 5...
    So here are my questions:
    At this point my hunch is that the plants need more hydrogen peroxide than an inoculant like Hydroguard to lower the level of pathogens.
    Is that a correct assumption? Would you recommend just going with hydrogen peroxide to kill any rot residual for a few days? Or use bleach?
    When to introduce Hydroguard?
    A few pics here...
    THANK YOU IMG_1789.jpeg IMG_1791.jpeg IMG_1792.jpeg IMG_1793.jpeg IMG_1794.jpeg
  2. the bubbles under each are coming from the air stones under each root
  3. The H2O2 is for disinfection by oxygenation. It also provides extra oxygen to the roots. By adding peroxide in the presence of the hydroguard, you are neutralizing some of the peroxide by killing the Bacillus amyloliquefaciens (ie. hydroguard). Kinda circular this ...

    If I had root rot, which I have before, I'd treat with peroxide flush for a few hours, even a day, in just water and peroxide. I'd then drain the res and refill with appropriate nutrient solution along with (your preferred beneficial organisms).

    I don't use bleach as it introduces masses of chlorine to the system/roots and the plants won't like that. Just use up to 1% (v/v) peroxide for a concentrated flush.

    Also like to add that Garden Friendly Fungicide also contains Bacillus amyloliquefaciens as does Hydroguard but at much more concentrated levels for less money.

    Also, I use Rootshield (Trichoderma harzianum strain T-22 and Trichoderma virens strain G-41 to protect from a broader range of root diseases at a wider range of temperatures), and Soil Activator (Bacillus subtilis, Bacillus amyloliquefaciens, Pseudomonas monteilii) as it gives better protection imo. The soil activator product does stain the water, but i don't mind.

    Lastly, I recommend members to review this article on the sterility of hydroponics. Its a good read ;)
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  4. Thanks and thanks for the links which I will definitely look at!
    I did do a peroxide flush and 4-hour soak, of the unit and of each plant, followed by a 4-hour Hydroguard soak before putting them back into the unit with fresh, filtered water and a high level of Hydroguard.
    I have three plants in there... one air stone under each one so plenty of oxygen.
    But after 24 hours the roots still smell a little moldy... which is why I was wondering if I should just switch to peroxide until the infection decreases... or if Hydroguard is enough.
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  5. I have been dealing with this for probably 5 days now. Haven't given them any nutrients because my understanding was that it was better to wait. I have Revive from Advanced Nutrients... could add it but I wasn't sure if I should focus on peroxide and infection reduction, Hydroguard first.. if the nutrients would cause a problem.
  6. You want to kill and then re-innoculate with the hope that the beneficial organisms will outpace the other weakened population. If you've already done that, then you've done what you can.

    Is your reservoir cooled?

    I implore you to look over some of my work. I'm not trying to be cocky, and have run into many problems before (and still do), but I think if you are interested in hydro/aero systems, you should consider some of my experiences.
    Aeroponic model 4Z0 Stoner Experiment #1745188 rev_2.b
    my current grow:
    Bato of the Systems

    I'm sharing this because I sense the problem is your rig's design. I'm not sure though, but it seems awfully small for three plants.
  7. Hey trojan,
    Thanks... you confirmed my suspicions...
    I will certainly look at your videos, super appreciative.
    It is cool. There were a few warm days so I think that favored growth of pathogens.
    I only have 3% hydrogen peroxide. I have 10l reservoirs.
    Most sites say 3ml per liter but is there a risk to adding more to kill off the existing pathogens?
  8. to reach a final concentration of 1% would take a lot of 3% depending on the volume.
    you would need 1/3 of the volume to be 3% and the other 2/3 would be water.
    So if you are soaking in say 3 L of liquid, 1L of that should be 3%, not 3mL per L. You would need 333mL per liter to be 1%. Let that bubble for an hour or two, rinse off the roots, and then inoculate and feed.
  9. Well I pulled out the big guns and poured 200ml into a 10l tank and let it do its thing overnight.
    Today, the rot smell is entirely gone. The water has turned a tad bit cloudy and there is some debris but I am crossing my fingers that this took care of the rot.
    In a few hours it will be 24 hours at which point the H2O2 will have broken down... will rinse and then inoculate. Would you suggest a higher amount of Hydroguard? And feed at the same time?
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  10. You guys dont think a chiller or putting blocks of ice in the reservoir is your first line of defense against root rot ?
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  11. Tried that... and continue to keep it cool but this time around I suspect the rot was well in place so I had to take more drastic action to lower the pathogen levels...

    In fact, I think one of the things that caused this was a few days where the tank warmed up. But correcting this has been a royal pain in the behind...
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  12. We are thinking differently.
    Has anyone ever seen a cannabis plant get root rot in a hydroponic system when the reservoir is maintained at 65 to 67 degrees F ?

    I haven't ..........

    My thought is to buy a chiller, make chiller or start adding blocks of ice to your reservoir.
    You can't let the reservoir get above 70degrees F
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  13. As I mentioned there were a few days over the past month when the temperature far exceeded 70 degrees. I believe this is what caused the initial growth which may have slowed when I began religiously cooling the water. But at that point the contamination was entrenched.

    Since that time, the tank has been chilled. Additionally I have taken the steps I outlined (hydrogen peroxide, sterilizing the tank and aquarium stones...) but that alone at a low temp was not enough to get rid of it.

    Today after using much more H202 for 24 hours the smell is finally gone... so I am hoping that later tonight I can empty the tank, refill with fresh filtered water and add nutrients. And cross my fingers.

    Hopefully that makes more sense.
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  14. You know I know it. I advised @paestum to review my linked threads. Did you look at the DIY reservoir I built? It's maintaining <70F and am so happy with myself. I was going to build another one since I ordered 10 new peltier elements...
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  15. My main point was to never let the reservoir temp exceed 70 degrees F
    Your pump and sprayers most likely got clogged .
    What is the PH of your reservoir with he H202 in it ?
    Are those auto flowering plants ?
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  16. Agreed but that already happened :)
    Now it is 7.3 but I am going to empty it the tank and put in fresh water.
    Would 7.3 indicate infection persisting? Hence add more H202 and bring the PH level down? I have PH down...
    Yes, they are autoflowering.
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  17. The plants are done ............. its is at least 30 days to get the plants to start to recover.

    5.8 to 6.3 is what you want ,,
    You keep on saying your adding in nutrients, no plant can survive without minerals .
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  18. No, I said this is the end of 24 hours of hydrogen peroxide. The ph level before was 4.

    Now I have to drain and add in the inoculation (Hydroguard) and nutrients...
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  19. I advised to start with a 1% peroxide flush. I did say somewhere up there for a few hours, or possibly overnight. Personally, I think one hour is fine. I don't remember saying anything about 24 hrs. The H2O2 wash is done in water. Its done to clear (some of) the pathogens. The pH is redundant in this case. I then advised to drain, rinse, and then add nutes & bennies (at appropriate pH).
    I've had plants recover the next day using the outlined method, but yea... autos. I just killed an auto and it was much healthier than those shown.

    But there are multiple problems I can kinda see/presume in this operation.
    You should be growing regular seeds until you get the hang of it because autos don't leave much room for messing up.

    i run em 5.5 - 6.0 but yea...

    I think some bacteria will produce organic acids and drop that pH, but that doesn't really say anything. Your res is too small for these plants, and the plug hole is too small, which will lead to the stem getting cut in = infection.

    Give it a day or two, but there is a lot of damage done. Fingers crossed for you.
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  20. Thanks. I had tried an hour before posting and then after sterilizing everything and starting over, when putting them back the rotten smell would appear the next morning. The infection was clearly very much still there.

    So last night I left them overnight. This morning the foul odor was gone, the water looked clear but slightly white (almost chaulky) and there were bits of small dead roots in the water. But the roots *looked* healthier (probably because the H2O2 had whitened them...)

    In total they were in the H2O2 for about 18 hours... 200ml of H2O2 in 10L of water. I took them out this afternoon after reading these messages (I was going to wait the full 24 but decided against it)

    I did the best I could. I sprayed the roots with Revive (Advanced Nutrients) and then put Sensizym and Hydroguard and 50ml of Revive nutrients in the water. All I can do now is hope that they stabilize. Pisses me off to no end that I was two weeks away from harvest.

    I didn't realize that the autos were more fragile. Come to think of it the feminized ones I were more resistant when this happened before. It almost makes the extra few weeks worth the wait.

    I learned a lot this time...

    First, 3 plants is too much for a 10l /2.5 gallon's basically asking for trouble.
    Second, I need to change the water in the tanks occasionally and make sure there isn't an overload of debris.
    Third, be super vigilant keeping water temps low, ensuring zero light and monitor pH levels.
    Fourth, add more oxygen. I was using one aquarium stone. I switched to one under each plant.

    You live and you learn.... sadly the Aerogarden is all I have here. Electricity consumption is very carefully monitored so building another system would not be a good idea. Plus my level of consumption is very moderate.

    But losing 3 months is annoying as heck.

    I thank you both for the insights... it's a learning process!
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