This one is a new one to me. Converted my auto grows from containers to grow bags, now I have white mold growing on the outside of the bags. Doesn't seem to hurt anything; two plants in full bloom and two just starting bloom. Not too concerned, other than I wish it wasn't there. Air temp is 70 degrees. RH is 50%. Any thoughts?
White Mold On Grow Bags
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This one is a new one to me. Converted my auto grows from containers to grow bags, now I have white mold growing on the outside of the bags. Doesn't seem to hurt anything; two plants in full bloom and two just starting bloom. Not too concerned, other than I wish it wasn't there. Air temp is 70 degrees. RH is 50%. Any thoughts?
Is it really mold or is it from liquid fertilizer? I get white stains that are from fertilizer salts. Is it a bit crusty?
Same. The salts turn my bags white just like that. If it is mold, then they are staying too wet too long.
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Is it really mold or is it from liquid fertilizer?
Never thought of that, but it could be. Sure looks like mold though. I can rub it off with my fingers. I doubt if it's overwatering; I always let them dry out almost to the point of wilting before watering - this actually happened once, and then the "mold" did get brown and crusty. Soil in two bags is HP Promix; the other two have Happy Frog with amendments (2 parts coir, 2 parts soil plus 1/2 part Perlite). Not much difference between the four bags, although the two bags with Promix have a slightly heavier "infestation." This would figure with Promix, as it has a wetting agent and retains moisture longer. I saw this with my last crop as well, although that crop came through just fine.
Never thought of that, but it could be. Sure looks like mold though. I can rub it off with my fingers. I doubt if it's overwatering; I always let them dry out almost to the point of wilting before watering - this actually happened once, and then the "mold" did get brown and crusty. Soil in two bags is HP Promix; the other two have Happy Frog with amendments (2 parts coir, 2 parts soil plus 1/2 part Perlite). Not much difference between the four bags, although the two bags with Promix have a slightly heavier "infestation." This would figure with Promix, as it has a wetting agent and retains moisture longer. I saw this with my last crop as well, although that crop came through just fine.
Odds are it's fertilizer salts then.
Bob Loblaw
Well-Known Member
I thought it was salts at 1st too but then I looked at the picture. It sure looks like mold to me not sure what you all are seeing there.
I've read before that white mold on soil was not as concerning, I know nothing just saying.
You could spray it down with a very strong peroxide solution I guess. The peroxide will not hurt the plants.
Hmm looks like white mold on a brand new bag...hmmm makes me wonder. I would definately be putting those bags through a washer with some soap after this grow.
Somethings not right there. Looks like mold on the rack underneath as well.
I've read before that white mold on soil was not as concerning, I know nothing just saying.
You could spray it down with a very strong peroxide solution I guess. The peroxide will not hurt the plants.
Hmm looks like white mold on a brand new bag...hmmm makes me wonder. I would definately be putting those bags through a washer with some soap after this grow.
Somethings not right there. Looks like mold on the rack underneath as well.
Sueet
Well-Known Member
The smell of mold is usually pretty obvious, does it smell of mold ?
I agree that if it is mold, it is staying too wet for too long. I am also really wondering what those bags are made of if it is.
I agree that if it is mold, it is staying too wet for too long. I am also really wondering what those bags are made of if it is.
Charmanderrr
Well-Known Member
Is it in the fabric or on the fabric? I would think it’s calcium deposit. Scratch some off and see if it’s like a powdery battery acid texture. That would mean you’re good to go. If it’s furry and soft it’s mold. If it is mold it will spread and should be taken care of. When calcium builds on a surface like a fabric it’s known as efflorescence and it can turn brown when it’s damp. But you said it’s brown when it’s dry? I don’t know of any molds that change colors like that but I don’t know if efflorescence that dries into a brown color either.
It’s chemical salts and it happens even if you don’t use bottled nutes…. my grow bags containing living organic soil are the same way. It’s from various soil ingredients reacting and leaving a deposit on the fabric.
No worries, no need to flush, dump or recook the soil and wash the grow bags after each harvest.
No worries, no need to flush, dump or recook the soil and wash the grow bags after each harvest.
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It is mold, and I think you're on to something. After this grow, all my bags are going in the laundry.
Thanks for all your help, people. I'll keep all your thoughts in mind. I have friends in "high" places!
A good possibility it is the deposits which are salts and dissolved minerals for nutrients the grower added or even from the soil itself. A follow up on "what If it was mold" it would have to be growing on the soil inside the pot since mold rarely grows and feeds off of plastic.
Plastic, and more plastic. It is strands of plastic, most often a type of polypropylene. If a natural material was used there is a good chance the stuff would start to decompose in a matter of weeks, especially those grow bags that sit in a saucer or directly on the ground outside.
Some of the cloth bags are made out of felt. From the wiki page on "felt":
"Felt can be made of natural fibers such as wool or animal fur, or from synthetic fibers such as petroleum-based acrylic or acrylonitrile or wood pulp–based rayon."
Back to the decomposing of natural materials if an organic felt is used to make a cloth growing bag.
As Bob says, think I'd H2O2 everything to be on the safe side
Guys, you can see that it's fuzzy when you zoom in. It turns brown when it dries because it's dying.
It's either mould or fungus, the real question would be, is it harming the plants?
It's either mould or fungus, the real question would be, is it harming the plants?
Bob Loblaw
Well-Known Member
What Melville said ^
You can see that it is a fuzzy mold if you can't see that then you need a new monitor asap and/or I'm worried about your driving.
Salts are scalely mold is fuzzy, this picture is as fuzzy as fozzy bear it can't be any clearer.
White fuzzy mold... that is the real question here how bad is it, what is it, should he be worried?
You can see that it is a fuzzy mold if you can't see that then you need a new monitor asap and/or I'm worried about your driving.
Salts are scalely mold is fuzzy, this picture is as fuzzy as fozzy bear it can't be any clearer.
White fuzzy mold... that is the real question here how bad is it, what is it, should he be worried?
White mould isn't a problem for your plants but does attract fungus gnats, looks unsightly and the words 'plants' and 'mould' don't belong in the same sentence
Charmanderrr
Well-Known Member
Could you edit the picture and show where you see the fuzz maybe? I’m using an iPhone 12 pro max screen with 20/21 vision and I do t see any, the picture itself just isn’t clear enough.
To me it look like a mirrored image of this pot which indeed has efflorescence. I don’t know of any mold that change colors back and forth from being wet and dry. Melville mentioned it dying but if that were the case it would not have turned back to white. The brown below the white in this picture is actually from the deposits too.
I also have salt & mineral deposits around the drain holes on my hard sided plastic pot. There is both brown and white deposits.
Since this morning I have done similar to what @Melville Hobbes mentions. I grabbed the photo and enlarged it. I still cannot tell whether it is minerals or mold or a combination but there definitely is some fuzzy area about half way down the side of the pot. That area is slightly out of focus because it seems the camera locked in on the area where the soil and top edge of the pot is.
The reason I now believe that mold is involved is because what looks like the upper left corner is covered in white fuzz. While not impossible it is not usual to have mineral & salt deposits show up that far up the side, almost to the soil line.
I did not enlarge this copy but the areas that are really fuzzy looking are circled. Forgot the photo
but caught it so here it is.Hey I’ve been wrong before - plenty …. and might have screwed pooch once again here
When your soil mix is rightly tuned and you put a few fan leaves on top of soil - the microbes & mycos will spin a white whispy web like substance on top as it breaks down the foliage. But yeah after checking zoom it could be mold.
fer sure I’d nuke it between runs…
curious are you growing in basement or garage, were these bags stored on concrete slab?
When your soil mix is rightly tuned and you put a few fan leaves on top of soil - the microbes & mycos will spin a white whispy web like substance on top as it breaks down the foliage. But yeah after checking zoom it could be mold.
fer sure I’d nuke it between runs…
curious are you growing in basement or garage, were these bags stored on concrete slab?
@SmokingWings is right, those are the areas I was referring to, as well as the bottom edge of the pot in the pic.Could you edit the picture and show where you see the fuzz maybe? I’m using an iPhone 12 pro max screen with 20/21 vision and I do t see any, the picture itself just isn’t clear enough.
To me it look like a mirrored image of this pot which indeed has efflorescence. I don’t know of any mold that change colors back and forth from being wet and dry. Melville mentioned it dying but if that were the case it would not have turned back to white. The brown below the white in this picture is actually from the deposits too.
The mould wouldn't be completely dead as it dries out. It's resilient stuff. It can easily go dormant and revive as the water comes back. As can many forms of fungus.
As far as mould and fungus always being bad goes, the promix has mycorrhizal fungi spores added to it as it forms a symbiotic relationship with the plant. It colonizes the roots and exchanges nutrients and sugars.
Not saying that's what is going on here though.
