Guide to Getting Rid of Root Rot

growweedtoday

Well-Known Member
Root rot is a condition found in both indoor and outdoor plants, although more common in indoor plants with poor drainage. As the name states, the roots of the plant rot. Many cases of root rot are caused by members of the water mould family Pythiaceae. This family includes a genus (type) of mould known as Pythium which was once classified as a fungus because it responds like a fungi to many sorts of treatments. Pythium is also part of the parasitic oomycete class, which are considered to be micro-organisms. I am not a major in micro-biology, but I believe all these terms which apply to the cause of root rot may help explain why there is sometimes confusion about whether Root Rot is caused by a mould, fungus, or bacteria.

Regardless of how you classify root rot, the methods to prevent and treat root rot are well established. You may hear that root rot will end up being lethal to your crop, but many growers (including myself) have successfully beaten root rot and been able to smoke the rewards. Even more importantly, growers need to take the steps to prevent root rot from happening in the first place. From what I understand, the organism that creates root rot is almost always there in your system. In order to prevent it from taking over your whole system and actually affecting your plants, you need to create an environment where root rot just can't survive. Luckily, most of the things you can do to prevent root rot will also benefit your plant so it's a win-win situation.

I would like to share my experience and research on preventing and treating root rot, and I would love to hear feedback from other growers about what has worked for them!

Prevention (these things will also help you control a root rot infestation)
Root rot mostly affects hydroponic systems, but can also result from over watering your plants in soil or other medium. Basically anytime the roots are sitting in water, they are at risk of devloping root rot. In order to prevent root rot, you will need change the plant's environment so that root rot no longer has a good place to grow.

  1. Cleanliness is one of the best preventions for pretty much any sort of plant pathogen. Keep your grow area as clean as possible at all times. Clean and disinfect all your equipment thoroughly before each new grow. Maintain a clean reservoir that is free of any dead roots, dead leaves or other types of plant debris because they will provide a rotting breeding ground for bacteria.
  2. Some people like to add beneficial bacteria to their water to help prevent root-related plant diseases and help make nutrients available to the plant. Some of the formulas available are Piranha, Aquashield, VooDoo Juice, Great White, Biozome, Subculture, Rooters, Plant Savers, Micro-Max, and DTE Soluble root enhancer. Most of these can be used with both hydro and soil grows. I personally recommend Subculture B because I've used it successfully to treat Root Rot. I've also personally heard many great things from other hydroponic growers about Aquashield, which is much cheaper.
  3. If you have a hydroponic system, it's a good idea to change your reservoir water regularly in order to prevent any one type of bacteria from overgrowing the whole reservoir. I personally recommend trying to change your water at least once a week. Regularly changing your water will also help your plants get better access to nutrients and the roots of the plant love that 10-15 minutes where they get access to the oxygen in the air (just don't ever let the roots get dry).
  4. It is beneficial to try to get as much oxygen as possible disolved in your water. Therefore it's a good idea to buy a BIG air pump and big air stones for your hydroponic system. Root rot can't thrive in an oxygen rich environment and the plant's roots love it.
  5. Ensure that the temperature of the water never gets warmer than a comfortable room temperature. Warm water holds much less disolved oxygen than colder water and also provides the perfect environment for bacteria. The maximum recommended temperature for the water in your reservoir is around 72°F (22°C). Trying to maintain water temps around 65°F - 68°F (18°C - 20°C) seems to be optimal for both plant growth and root rot prevention. When your temps are higher than that, there's less oxygen in your water and a better opportunity for bacteria to grow.
  6. Don't let any light get to your roots or reservoir water ever, as it provides heat and light which will promote the growth of bacteria.
  7. SM-90 also seems to help prevent and treat root rot, as well as help your plant overall root health. It's made up of a few different types of oils that happen to kill many pathogens. I also like to have SM-90 around because it will kill aphids, spider mites, and white powdery mold when used as a foliar spray. I personally feel that anyone who grows hydroponically should have some SM-90 around. I've heard that SM-90 may kill beneficial bacteria, so I don't use it if I'm adding Subculture B. I always use one of the other. I would be very interested to hear other people's experience with combining the two(beneficial bacteria and SM-90).

Treatment (when you already have root rot)
If you don't fix the environmental causes of root rot, then it will just keep coming back no matter what you do. Therefore, it's important to go through the list above and make sure you're covering all your bases to prevent a re-occurrence. It's also important to note that affected roots will likely never recover, just like how discolored leaves on the plant will never recover. What you're looking for is new, healthy white root growth.

As far as how to get rid of root rot, using Subculture B (by General Hydroponics) has personally worked for me. I had a 6 gallon Stealth Hydro (top-fed DWC or bubbleponic system) and all my plants were suddenly afflicted with horrible, brown, smelly root rot. I treated the system with Subculture B and changed the reservoir water completely 1-2 times a week. 3 weeks later my root rot was gone. No dead roots or anything, the micro-organisms in the Subculture B ate everything. I have continued to treat my water with Subculture B as a preventative.

I have also heard really great things about AquaShield, which is much cheaper. Once I am through with this container of Subculture B, I am going to give AquaShield a try.

With my hand-watered coco coir grow, I use SM-90 with every watering because my plants seem to grow more quickly and have healthier roots, though I haven't run any controlled experiments. This extra growth inspired me to try SM-90 as an additive in my DWC setup. I haven't had a re-occurrence of root rot with any plant fed water that has been treated with SM-90. However, that could be because of other prevention factors so I don't know if it's the SM-90. I haven't personally tried using SM-90 alone as a treatment for a plant that already has root rot, but I've talked to other growers who've said it will work alone as a treatment for root rot. I would definitely be interested in hearing other people's experience with using SM-90. From what I understand, the SM-90 will kill any beneficial bacteria, so I haven't tried using SM-90 together with Subculture B.

I've also heard some people report success after treating their system with a drop or two of bleach/Chlorox per gallon of water. I have personally never really tried this method because the Subculture B and SM-90 both seem to work so well, and also I'm leery about using bleach unless I absolutely have to.

Not Recommended
Some people like to use hydrogen peroxide to kill all organisms in their reservoir. The conventional wisdom is to add a teaspoon of 35% hydrogen peroxide (buy it from a hydroponic store) per gallon of water in your reservoir. Some people also use the hydrogen peroxide you get from the store and use that directly on the affected roots. It does seem to do the trick in the short term to get rid of the brown slimy roots. However, in my experience, the roots will appear to be doing better for 1-2 days, but end up getting root rot right back. I personally believe that this is because the H2O2 (hydrogen peroxide) kills all the organisms in your water (both good and bad) but is then used up very quickly and is undetectable in the water after a day or two. If even one pathogen survived the H2O2, it now has the perfect environment to spread (no competition, nutrients in the water, and the H2O2 has all been used up) It seems like you would have to be constantly adding H2O2 to your water in order to use it as a treatment for root rot. In any case, based on my own experience, I have never been able to successfully treat root rot with H2O2 (not for lack of trying!) so I strongly recommend against using the H2O2 method as a long term fix for root rot. If someone out there has successfully rid their plant of root rot using just H2O2, (and by successful, I mean you were able to eventually harvest the plant) please post your methods!

Feedback
I would love to hear feedback from anyone else that has successfully beaten root rot in their hydroponic system. There's so much mis-information that gets spread around about preventing and treating root rot, and it would be great to hear from people who have real experience beating it. If you have any suggestions of things that should put taken off or put on my list, I'd love to hear from you too!

From this to this:

 

loolagigi

Well-Known Member
short version....clean bucket, add h202, 1tbs per gallon. make sure you have lots of bubbles, and keep your res temps down. light proofing is important too....Loola
 

growweedtoday

Well-Known Member
I have never been able to successfully get rid of Root Rot with H202. It always works for a day or two but the root rot seems to keep coming back. Do you just keep added H2O2 all the time? Could you share your methods?
 

dipstick

Member
I had a nightmare with the rot and talked to and tried everything and everyone under the sun about it... I tried hydrozyme"made it worse", tried great white"seemed to work for a couple weekes then bam" and keep my shit clean and everything, so I finally bought a bottle of 29% h2o2 and some sm-90 and between the two i havnt changed my water in over three weeks and it is clear and clean as hell!!! I add a couple of teaspoons of the h202 every three or four days and a couple of teaspoons of sm-90 every seven days or so but i havnt added any this week cause i havnt changed the water yet and i dont want too much in there but the h2o2 goes away, i wanted to see how long it would go and stay clean and so far so good!!! i really have had a long bumpy road with root rot it has killed my first 4 grows in a dwc which happens to be my first time growning indoors so it has been very depressing and i found myself ready to give up before i even had any success, but now a new light shines on my hydro grow and that ray of hope is h202 and sm-90
 

Power Towel

Member
I can attest to H202 and SM-90. I put a little SM-90 in during res changes, and I add 1 teaspoon of H2O2 per gallon EVERY THREE DAYS. Water is always clear as a bell, roots are completely slime-free, just a little browned from the FloraNova nutes. Of course, I have only one grow under my belt, grow 2 is underway, so maybe this time will be different. I hope not. :)
 

dipstick

Member
And the really funny part is i spent a couple hundred dollars on miracle cures and that bottle of 29%h2o2 cost 8 bucks for the big bottle, and the sm-90 wasnt too bad either, compared to other stuff these products have been effective and much cheaper...
 

growweedtoday

Well-Known Member
I've never had luck using H2O2 (hydrogen peroxide) by itself to kill root rot, but from other people's posts, it definitely seems to do the trick if you use SM-90 too. Has anyone successfully been able to kill root rot using just SM-90?
 

dipstick

Member
i will try to use just the h202 for couple weeks and then just the sm-90 for a couple a weeks if that will tickle your fuzz it will mine
 

growweedtoday

Well-Known Member
I will do an experiment too, half my plants treated with just H2O2 and half with just SM-90. I just started a grow so I will post back my results at harvest or at the first sign of root rot, whichever comes first!
 

Power Towel

Member
my understanding of sm-90 is that, in addition to it's anti-<insert-microorganism-here> properties, it is a "wetting agent" which helps "spread" the water around better inside the otherwise dry areas of the reservoir. Combine that with some h202, and you are "spreading" that around also. I can't speak to the rot-curing aspects, but if you have enough H2O2 floating around at all times, stands to reason it would keep anything from getting "worse" - and if you do it from day 1 - well - do the math. But that was my first grow - obviously multiple grows are needed. I'm sure plenty of folks here have use 1 tsp / gallon of H2O2 every 3 days, or something close to that, for several grows, at all times. Would be interesting to know if they ever got a problem of any kind in the reservoir.
 

SCOTTYBALLS

Well-Known Member
H202 ... I add it in my top off water and My res temps see70's even 80's on a regular... No root problems here ... I use a GH waterfarms and keep water pumping with a big ass air pump
 

stillcantroll

Active Member
I think it's very important people reading this understand that h2o2, sm-90, great white, etc are not cures to anything. They are band-aid treatments to an underlying problem. The second post is correct. You must invest in your setup properly. A 68 degree, lightproofed, DWC with tons of bubbles and good quality water will not get rot. H2o2 and those things should be a solution for a grower who experiences, for example, a power failure and a sudden spike in temperatures allowing cultures to develop.

If you think you have enough bubbles, go to the hydro store, buy some pumps/stones and double them... you'll thank me later.
 
I currently have root rot and I am looking for a thread just like this one. I am bumping this to the top even though its 3 months old cuz I think its a good thread and good for people in my spot. I only wish we got more correspondence from those who like sm-90 + h202, as far as the issue if whether one works by itself or not.

I think what we'll see is that the h202 might work good to keep the stuff looking clear it isn't really a cure.
 

HerbalRemedy

Well-Known Member
I use black reservoirs 5 gallon and lids, air pumps rated for 50-100 gallons. Fresh airstones at the very bottom of the reservoir. Clean water, and I use h202. I usually just eyeball pouring a little in on a weekly basis. Seems to work for me. I had a problem with root rot before but it was seemed to stem from the fact I wasn't producing a lot of bubbles and I had major light leaks using those cheap thin plastic totes as the reservoir. H202 helps to keep everything clean though. I also use H202 in my aquarium and it stays spotless and I never have to clean it.
 
I have an 18 gallon rubbermade with 5 super lemon haze. They are still small, and struggling to get big, they are maybe 5-7 inches tall. I also have a dinafem haze auto and road runner (also autoflower), these are each in their own 5 gallon black bubble buckets. The 18 gallon rubbermaid has 2 air stones being pushed by a whisper 100. It is foil taped (there WERE a few tiny light ... like pinhole sized or maybe just a bit bigger leaks) but I have a hole in the top of it for ph and nutes. Well I left that hole uncovered one day for a few hours. I then noticed algae in the sight indicator. Yep, the roots are covered in brown shit.

The ones in the black bubble buckets are unaffected. Roots look great.

Also not helping were the temp problems I was having (now resolved).

Also, I've been using flora nova nutes, which are way thicker than the regular flora nutes (which are not thick at all they are almost like colored water). I think the flora nova nutes make the plants look suspect even if they are ok anyways. I'm glad I now have regular flora nutes which I ordered. These are general hydroponics nutes in case anyone's wondering.

So I just ran my fingers all through the roots and pulled out as much of the algae/crap/?rot? as I could, some roots did tear and I threw them to the side. I treated with h2o2 since I don't have any sm90 or the other product the OP recomended. 5 ml per gallon. Also, I am gunna order the sm90 I suppose, cuz I really need these plants to take off... The road runner and the haze are way way bigger than these slh's...
 

FeFiFoFUM

Active Member
Ive battled root dissease , root rot was the first battle I had when I transplanted from a top feed to a dwc mid flower, SM-90 and H2O2 worked well for that, I added 3ml/gal of H2O2 at res changes and 3ml/gal of sm90, then 3ml/gal of both every three days, took a couple of weeks but it dealt with the root rot, Right now IM recovering from Brown slime algae, and H2O2 nor Sm90 do shit for that, So I started using beneficial bacteria, but I dont just add subculture to the res, I make a tea and innoculate that way, You cant run bennies and h2o2 sm90 together its either or, and I believe that bennies are better since they treat root rot, and other root dissease that h2o2 and sm90 wont, they also give you more room on ressy temps, and are more forgiving if you have light leaks, subculture b is expensive, so is subculture M (the other half of the ingredients in the tea) and making the tea makes the products last longer

so in short i wont be using h2o2 anymore, and sm90 just to help fight insects, or use as a wetting agent maybe. Bennies all the way
 

Heisenberg

Well-Known Member
sm-90, Zone, H2o2 and physan 20 will all purge root rot IF you also correct res conditions. Just correcting res conditions alone will show a huge improvement. Stillcantroll is correct saying that a properly maintained res should never get root rot. You might however get the brown slime despite doing everything right. It doesn't play by the same rules.

Adding beneficial microbes will rid your res of just about any detrimental microbes, including rot, gunk and slime, and let you easily get away with less than perfect res conditions, within reason. I personally would still sterilize the roots first.

If you have sterilizing agents and decide to go with bennies, you can no longer use them in your active res. You can however still use them to sterilize tubs and equipment between grows and to wipe down walls.
 
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