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Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 2:23 PM CST
Hi everyone,

I'm wondering if there are any known causes of root rot BESIDES overwatering?
For example, can the responsible bacteria already be present in potting mixes or organic fertilizers? Anything else you can think of?

I've recently potted a few rooted cuttings and several of them rotted - luckily I caught it in time. I think the pots were a little too large, i.e. held too much water. Still, it seems strange to me that so many were affected at once. So now I'm wondering if there were any other factors at work ...
I potted them in a self-made potting mix made of coco-coir, perlite, and worm castings.

Thank you in advance.
[Last edited by Rynoa - Aug 25, 2020 2:24 PM (+)]
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Name: tarev
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tarev
Aug 25, 2020 2:41 PM CST
Yes, container size matters, also depends what plant you are planting. You mentioned rooted cuttings, if they were rooted using water, then they suffer when moved to soil.

Also some plants cannot take too much direct sun, so it may be a combined reason, not just overwatering but also excessive sun/heat.
Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 3:10 PM CST
@tarev
Thanks a lot.

Some of the cutting were rooted in water, but most I've bought online and they were shipped in soil (and no signs of root rot at the time, plants seemed very healthy). I assumed they were rooted in soil also - or at least already established in soil.

I've heard of the 'water roots' being different than 'soil roots', but I've had better success rates rooting in water versus soil. Do you have any tips on how to make the transition as gentle as possible for the plant?

All plants were near a south-east facing window. Some might have gotten a bit of direct sun in the morning, but most got indirect bright light. I wouldn't think that would have caused any problems?!? Good to know though.
Name: Lin Vosbury
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plantladylin
Aug 25, 2020 3:41 PM CST
Root rot is often caused by a dense potting medium that retains too much moisture, deterring proper drainage. When a dense soil doesn't have sufficient aeration, oxygen is depleted and the roots suffocate and rot. For the past 15 or more years I've been using a mixture of potting soil, perlite and coconut husk chips (or orchid bark mix) for all of my plants. It makes a very chunky, airy mixture that drains quickly.

I've rooted cuttings in water for almost 50 years and many times I've had difficulty getting those fine watery roots to acclimate to soil conditions. Nowadays if I take cuttings, I either just immediately pot them in soil, or I put them in jars of water and just allow them to continue to grow in the water. I have a few vases/jars with Pothos and Philodendron that have been growing in water for a few years now. I just have to remember to change the water out every couple of weeks so that it doesn't get rancid.
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ediblelandscapingsc
Aug 25, 2020 3:49 PM CST
Fungus gnats can really do a number on rooted cuttings also did you notice a bunch of gnats flying around the potted plants.
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Name: Zoë
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NMoasis
Aug 25, 2020 4:30 PM CST
I've had good results using vermiculite for cuttings, rather than potting soil, but I do mostly lamiaceae, which are generally not the hardest to root (although I've rotted many in water or soil).

As for your transplants that were shipped, I wonder if the worm castings were too rich right away? I know they are technically not "fertilizer" but depending on the much-varied info about them, they do contain some level of nitrogen and other nutrients.
For me, gardening is really just an excuse for playing in the dirt. Admittedly, plants are a satisfying by-product.
Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 5:51 PM CST
ediblelandscapingsc said:Fungus gnats can really do a number on rooted cuttings also did you notice a bunch of gnats flying around the potted plants.

Would that only apply for a severe infestation? I have a few fungus gnats that I'm currently fighting with occasional hydrogen peroxide watering. Not a lot though.
Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 5:53 PM CST
@nmoasis
Do you think it might have burned the roots?
I also added a small amount of dynamite slow release to the soil. But since it was small amounts of both castings and fertilizer, I didn't think it would hurt the plant?!

I was 'suspicious' of the worm castings since it's organic poop, so I figured it might harbor bacteria. Burning the roots wasn't really on my radar .... hmmm ... Thinking
[Last edited by Rynoa - Aug 25, 2020 6:04 PM (+)]
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Name: Zoë
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NMoasis
Aug 25, 2020 6:07 PM CST
More likely the Dynamite. I honestly don't know about the worm castings; that was just speculation. Generally the rule of thumb (again, depending on who's talking Hilarious! ) is no fertilizer that stimulates leafy growth at the time of planting or transplanting, so that the plant can put its energy into root production. There are all kinds of exceptions to that, but I usually hold back any nitrogen fertilizer at first
For me, gardening is really just an excuse for playing in the dirt. Admittedly, plants are a satisfying by-product.
Name: sumire
Reno, Nevada (Zone 6a)
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sumire
Aug 25, 2020 6:11 PM CST
I would consider the peroxide watering a cause for concern. If it is strong enough to kill fungus gnat larva it is strong enough to start bleaching out root growth.
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Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 6:13 PM CST
That is very good to know. Never heard about that. How long would you wait to add fertilizer?

On the other hand, Coco-coir is pretty much sterile, so I figured I'd have to add some sort of nutrients?! Confused
Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 6:16 PM CST
sumire said:I would consider the peroxide watering a cause for concern. If it is strong enough to kill fungus gnat larva it is strong enough to start bleaching out root growth.

Hydrogen peroxide is actually often recommended to treat root rot. So I wouldn't think so.

I also dilute it to 0.3-0.6% strength.
[Last edited by Rynoa - Aug 25, 2020 6:21 PM (+)]
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Name: sumire
Reno, Nevada (Zone 6a)
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sumire
Aug 25, 2020 6:20 PM CST
Cure by breaking down the rotten material. Hydrogen peroxide loses a spare oxygen as it denatures, and that oxygen latches onto anything it can. Great when you add a drop to regular water, because it increases oxygen content. Great when it rips the cell membrane of bacteria. Not great when it destroys the cell walls of your roots. Its a definite use with caution.
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Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 6:41 PM CST
Since roots are made of cells, it would make sense that anything destroying one type of cells would be potentially harmful to all cells - I agree. Unless healthy plant cells are different from 'rot' somehow (I'm an engineer, not a biologist or chemist) - which I thought must be the explanation why it's considered safe to use (because that thought has occurred to me before first use). If that's not the case, why isn't the potential of destroying roots mentioned anywhere? I just googled it again and can't find anything about it. It's even recommended for 'strengthening seedlings' Thinking

Granted, the sources popping up aren't exactly peer reviewed scholarly articles (nor do I feel like reading scientific articles about this), but you'd still think someone would have noticed by now if it killed their plants?! Confused

Another point supporting your argument is that it's said to slow healing when applied to human wounds as it's also attacking healthy human tissue. But again, I figured human flesh cells are closer related to fungus gnat larva than plant cells (and again, I'm not a biologist ;) ), so I thought if so many are using it, it must be fine.
[Last edited by Rynoa - Aug 25, 2020 6:56 PM (+)]
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Name: Zoë
Albuquerque NM, Elev 5310 ft (Zone 7b)
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NMoasis
Aug 25, 2020 6:52 PM CST
Rynoa said:That is very good to know. Never heard about that. How long would you wait to add fertilizer?
On the other hand, Coco-coir is pretty much sterile, so I figured I'd have to add some sort of nutrients?! Confused


Give the plant a gentle tug to see if it's developing roots and holding on in there. Some people wait until they see signs of new leaf growth. Then feed half-strength at first to see how it reacts. Things like this are so variable and everyone has different methods, so I'm always hesitant to make hard & fast pronouncements. I agree about the sterility of coir and perlite. not sure what to suggest. I've never tried that combo, with or without castings.

For me, gardening is really just an excuse for playing in the dirt. Admittedly, plants are a satisfying by-product.
Name: sumire
Reno, Nevada (Zone 6a)
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sumire
Aug 25, 2020 6:54 PM CST
Its originally a method of clearing algae out of irrigation pipes to prevent clogs. The hydroponic growers picked it up as a safe method of flushing bacteria and algae in systems that need to be kept relatively sterile to prevent root rot. From there.... I think it has just been adopted wholesale because people didn't read the fine print and most times it doesn't simply kill the plant right off....

But plant cells and animal/bacteria cells react the same way to that type of chemical reaction.

If you are trying to root something, a drop in a gallon of water is great for adding oxygen to the system. And I have seen straight peroxide used on crown rot in phalaenopsis. It was a matter of burning out the bacteria before the orchid completely died.
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Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 6:59 PM CST
You seem to know more about chemical reactions and cell walls than I do ... So I'll add it to my list of suspects (which is getting annoyingly long)
Name: Sabine
New Mexico
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Rynoa
Aug 25, 2020 7:04 PM CST
@sumire
How long would you think it would take to develop into rot if the hydrogen peroxide was the culprit? Maybe that could help narrow down the causes.

I've only used it on those plants once and it was a few days ago (3-5 maybe? Don't remember exactly)
Name: Daisy I
Reno, Nv (Zone 6b)
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DaisyI
Aug 25, 2020 7:06 PM CST
I suspect it was a combination of Hydrogen Peroxide (burned delicate roots), worm casings (added a ton of bacteria), Dynamite (too much fertilizer for cuttings), too large a pot (so overwatering), Fungus Gnats (caused by overwatering)... They might have survived just one on this list but not all at the same time.
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Name: sumire
Reno, Nevada (Zone 6a)
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sumire
Aug 25, 2020 7:09 PM CST
I agree
I think that everything at once got the cuttings.
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