Damping Off Efforts

I have Damping Off Disease. Here is my research and my current solution/workaround to save my remaining seedlings. Damping Off is basically a fungus which eats the stalk of your seedlings at or right below the soil line and then moves along the stalk. It affects many plants, not just cannabis. And once your seedling has it, it dies. I have found no cure, only fixes to soil or coir to get rid of the fungus once it is apparent in the grow. Also it is contagious within the seedling space traveling from container to container. From Wikipedia (https://en.m.wikipedia.org/wiki/Damping_off):

A number of different fungi and fungi-like organisms cause the symptoms of damping off, including:

Alternaria species. Cause leaf spotting.

Botrytis cinerea – also known as “grey mould”. Symptoms caused by this often accompany other symptoms.


Macrophomina phaseoli – a plant pathogen that causes charcoal rot on many plant species including Zea mays and Pinus elliottii

Phytophthora – a genus of plant-damaging [oomycetes (Water_mold) whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural

Pseudomonas. Cause leaf spotting.

Pythium – a genus of [parasitic] oomycete. Once classified as fungi, and consequently sometimes still treated as such. Along with Rhizoctonia solani , attacks by Pythium are most associated with producing roughly circular patches of dead seedlings.

Rhizoctonia solani– a plant pathogenic fungus with a wide host range and worldwide distribution.

Sclerotium rolfsii– a corticioid fungus in the family Atheliaceae. It is a facultative plant pathogen and is the causal agent of “southern blight” disease in crops

Thielaviopsis– a small genus
of fungi in the order Microascales. The genus includes several important agricultural pathogens.

Late last night watched quite a few non-cannabis, agricultural videos looking for a solution to save my remaining seedlings, as well as going to mushroom cultivation sites to find out about sterilizing my coco coir.

Notice in the picture at the upper part of the stem by the cotylidon leaves, there is still remaining broad healthy stem for about a millimeter. But below to the roots, it is hair thin shrunken. This plant event occurred in less than 6 hours last night. So the next post has my solution effort.


As you can see, I still have healthy seedlings I want to protect. The dead seedling from the first post (regular World of Seeds Afghan Kush), used to be like that 24 hours prior. I am in a Catch 22: these seedlings were potted from their plastic bag yesterday morning 36 hours ago. And they’re strong- BUT if I don’t make some change I have to assume they are next. So first I completely stopped watering, and won’t for next 48 hours, and I also removed the humidity dome. But what else!?

How can I be sure I don’t have whatever fungus in the rest of my coco coir!?



The shroom websites suggest boiling water bath in an insulated container maintaining roughly 180 degrees F for over an hour, possibly 4 hours or more. One agricultural doctor showed how to bake soil on stovetop. Thus, I opted to bake my coir in the toaster oven for 2 hours at 380 degrees F. This should move the internal temp of the coir above 180 F for at least 30 minutes. Then when I rehydrate I do so with boiling water.

I apologize for the oven pic being upside down: it is not upside down on the phone or computer, and I don’t know how to correct it within the post- but whether or not right-side up: bake the HELL out of your coir and rehydrate with boiling water.


Try watering with chamomile tea. May sound weird, but does prevent damping off.


Finally, how is the mold transmitted from container to container?? Not air as often as one would think, but by runoff at the bottom of containers as containers sit in the runoff. So bleach bath your infected hardware and containers! Finally, I am taking draconian action on my early still-healthy seedlings. I will give them a dunk in 50% distilled water / 50% hydrogen pyroxide and then repot in my newly baked and boiled media. I hope this thread gives some hope to folks trying to save their expensive genetics from water molds.DampGood3


Some great info there, thanks. I’ve had it come up sporadically over the years but never as an ongoing thing.

One thing I’ll say is that with seedlings in coco like that I’ll wet the medium once at the start and usually won’t water again for like 4-7 days. They drink pretty much nothing at that stage so there should be lots of water in there for them to seek out.

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Pure coco with the seedling recessed into a depression that will hinder air flow and with containers that don’t have drainage, seems like a perfect way to encourage damping off.

Pure peat pucks without good air flow seem to encourage the same problem sometimes, but you have really perfected it - congratulations :grin:

If you get them into containers where they are closer to the surface and exposed to direct light as well as light to moderate airflow, AND make sure that the surface of the soil is not overly damp, I think you will see an improvement.

I personally think that the fungi that cause this are omnipresent and that it is more the conditions that we provide that make the difference. Some strains are just magnets for stuff like this, but I think yours is a setup to kill.


Well, from my standpoint, I had used this method with the seedlings since 1988 in this part of the country with no real humidity at all. But I’ve never used a dome and did so because of insects, so I’m again at Catch 22. Thanks for replying and I will keep you posted.


Well that’s a bugger then… not sure what to say other than I hope it turns around for you bud :crossed_fingers:

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Whoa, wait a second. You were using pure coco to start your seeds in '88?
What medium did you use in '88 to start your seeds and when was the first time you used the coco to start them?

I don’t have my written records handy-- let me call my documentarian and I’ll get back to you.

I’ve started seeds in almost every medium. The question was not whether the seedling sprouted, but why it stopped: which- in my grow-- was due to a water mold pathogen. It is not a typical experience for me but I think I found both the culprit and solution. I will be posting updated pics in the next post. I have video of the hydrogen pyroxide bath working.

I need to cut the size of the pics down on my desktop before posting so it will be several hours. So far, I may end up with over a 50% survival rate since discovering the problem, and that counts the 2 dead seedlings before I realized.


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I had a problem with damp off this year. Lost two-thirds of my Moroccan Beldia seedlings. It happened so fast for them, it was a total loss. But then I had it happen with one of my Tashkurgan plants. As soon as the plant wilted, I dug down around the base of the seedling at least an inch down into the soil, maybe more, exposing the stem that was rotting. I really didn’t have too much hope for the plant, but within a week it was standing back up on its own. Just exposing the stem to air solved the problem. Some years back I had one of only two very special seedlings get damping off. The stem was nearly eaten through before I even noticed. The plant only had its first leaves past the cotyledons. So I cut the healthy portion of the plant off and replanted it. To my surprise, it grew. Granted, it was stunted for a Time, but It grew into one of the best plants I’ve ever had the pleasure of smoking. From now on I will always be wary of what seedling starter soil I use. Smell the soil first and make sure it has it gone bad. Marketplaces will leave their stock out in the rain and snow and one little rip in a bag can let all that water in, making the soil go bad. I will never use compost again either. Not without cooking it first, as I’ve seen suggested. I think a black trash bag with the soil inside can accomplish the same thing as a stove.


Howdy Upstate,
Though I have not yet posted them, I have pics and video of washing my remaining seedlings in straight drugstore hydrogen pyroxide 3%, and it DOES knock off the brown killer slime. Some may be too far gone, but for my most healthy seedling with tap root and several major branches, I believe the long dunk in H2O2 coupled with transplant to newly sterilized (400 degree oven for 2 hours) dry coco coir will allow it to survive with possible mere transplant shock.

Also, I want to reiterate: if someone suspects early on “maybe somethings going on with my plantling” check the bottom of your container: if it feels slick or slimey, then do your best to get the plant out of that container into sterilized media after a H2O2 wash ASAP.

Just my 2 cents, thanks for replying. Update pics in a couple of hours.


Definitely what you did will work out. I would have used a hydrogen peroxide soak myself, but due to the damn covid :mask:I couldn’t even find any. I’m running into the same problem now, because I read that hydrogen peroxide and water can be used to combat powdery mildew, which I have been having a problem with for the first time. New genetics, combined with flowering plants in July and August in New York. I’m guessing you start your plants low in the container so that when they finally stop their seedling stretch, they come out about even with the top of the cup? I’ve been doing the same thing for 30 years. I never had a problem due only to low seedling depth, (I don’t think)but coupled with soil/compost that can hold a lot of water, seems to be a recipe for disaster depending on the genetics you use. The heirloom variety that’s from this area that I grow would never get damp off regardless of the conditions. However, my old Afghani line from northern Washington certainly does. I have to make sure the soil thoroughly dries out between each watering for the first couple weeks. By the way, this worked for my Moroccan as well… as I said I had no hydrogen peroxide, and I didn’t even have any other soil I could put the seedlings in that wasn’t Frozen at the time. I just let the soil get and stay very very dry, and that did the trick. I watered once just a little bit too early, and I lost one or two more. Following that, I kept the soil very dry. I just gave them enough to live . I’m looking forward to seeing how your peroxide wash works. I’m guessing it will work very well. Sorry you have this problem too, but I’m glad you’re writing about it so I can learn as well. Thanks for posting this thread.

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Here are some pics, the first is a major seedling, which had lost its shell but not broken the surface of the media, it was brown in two places and at the tip of its tap root and slimey, hit it with a two minute soak of H2O2, followed by a 2 minute soak in distilled water, followed a second 2 minute soak in H2O2, followed once again by a final soak in distilled and repotted in freshly sterilized coco.

The second pic is it repotted 36 hours later, notice the city lions have filled with chlorophyll and opened, it is much healthier, and fingers crossed, right now it looks like I save two female strains out of this ordeal, LA Peyote Kush and Bubba Kush.

It won’t let me upload the H2O2 video, but it was eating that mold/brown slime like nobody’s business. Also, sorry for the extra time it took to get these photos up, the landlord literally died. Like for real. Also Upstate, the cups were just default behavior from cloning and I wasn’t thinking; not good for fresh seedlings.


I have been thinking about this problem for a couple days and I’m wondering how much the soil around the base of the plant might be contributing.
The reason being is, I’ve always used the compressed peat pucks and never lost one (touch wood) and all pictures I’ve seen (with damping off issues) have been in soil.
It could be the peat pucks do not provide as good an environment for the PM (or just BS luck…) as some soils.
Perhaps some other folks might add some missing details to this.


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I’m using straight coco coir, I believe having them next to a shower stall passed the aquatic mold along the wet tile to the bottom of the containers. In the future, although will now be on a routinely bleached plastic “floor”, and mainly outside, I am looking to inoculate the media with beneficial myco before planting seedlings.


Also peat has antifungal properties if I’m not mistaken


Lol!!! Fu@#ing auto correct. I’m guessing you said cotyledons ha ha. Excellent you were able to save those plants. Nice tip.


Yeah i was having root rot sljme type crap in dwc early on in my curremt grow. H202 knocked it right out. Now I’m using a additive to promote healthy fungus and bacteria to combat it but yeah peroxode is legit

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