White Mold Please Help

Hello everyone! On my last grow I had mold for the first time towards the end of flower. Now it seems i can’t fight the mold even at veg for my current grow. Mold forms on the top part of the soil and the side of the fabric smart pots. I keep spraying with h2o2 but want to limit it since I am growing organic. I wait for the pot to be light and I then water again.

Humidity is at 53% temperature is at 78f.
I have a 250cfm inline fan running. With two ocilating fans inside the tent. The tent is a 2x2x6.

I have a 2 pint dehumidifier in the grow tent. What are my options is there anything I can do about the spores.

Just had the same thing but was way worse. clean the top of the soil by removing. spray lemon/lime juice in water, spray the soil and the leavs and the pot down. worked for me.

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Thank you you are the only one that helped

I have not had your problem, however. In between grows I sanitize my tent. I spray a bleach solution on whatever I am cleaning and wipe with a wet rag. I literally wipe, EVERYTHING. I wipe down the lights, entire tent (walls, floor, ceiling). Cords, heater fans, everything i use on the prior grow, up to and including tools. I can’t speak for everyone else but I do this and have never had mold or bugs in my 5x5x5. Hope this helps for at the very least, future grows. Maybe some more experienced ppl can help you with what you can do right now. Good luck! @BIGE @dbrn32 @raustin @HornHead @PurpNGold74 @anon35207245 @tanlover442


Sorry. I saw this but have no experience fighting white mold. Some people swear by peroxide with it. Ivee heard 1 pt h2o2 to 3 parts water. N ive heard full on peroxide splash. Problem is like you said organics. If your feeding microbes the peroxide will damage them. So… wait for advice is my advice :joy:. Sorry again


I would agree on the cleaning. Although that could just be from something in your soil or additives. Do you use a product like mycos or anything similar? I’ve read that active fungi or whatever else is in them can cause this stuff. Since it keeps showing up on top of pots, would be my first thought. I believe in most cases of this you can remove it and carry on.

It sounds like you’re doing everything else right otherwise. You can try letting pots go dry a little longer. Perhaps someone else will have some better feedback.

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Seeing that sort of white mould on the surface of dirt in an pot is normal, it’s what happens when you have moisture and a lack of air movement around the edges. I see that and I scrape off and discard the top quarter inch of soil.

As far as on the sides of fabric pots goes, there.are plenty bio fungicides out there you can use to clean that off.

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Thank you very much. Do you do 3 parts water 1 part bleach?

I don’t know what mycos is so I guess the answer is no. Thank you for your response.

But i have an ocilating fan pointed right at the pot.
Are there any organic fungicides you can recommend me? I grow organic so I don’t want to damage my microbes. Thank you very much for your response.

I can’t recommend because I’m in Belgium and products here may well be different to what you can get.

But you THINK that ventilation on the pot is good, but the nature of the beast is that there will always be a space with “dead air” in around the edges no matter what, same as I could run 12 fans pointing in all directions in my living room but I can give you an absolute guarantee that there will be “dead air” around where the walls meet the ceiling, it’s something that is nigh on impossible to avoid which is why I simply remove 1/4" of soil from the entire surface when I see the inevitable white fluff that always appears.


Mykos/mycos are a company that sells/boosts microbacteria. The good ones.

He was basically seeing if by ‘organic’, do you mean you breed good bacteria etcs in your soil. Which im pretty sure u are saying. Correct?


Any kind of mold means your soil is too wet. Let the pot dry out and scrape that mold off as best you can.


Yes organic soil is all about having goof microbes. Without them the plant will most likely die. So I don’t want to add a product that will kill them off.

Mold is caused by to much moisture and not enough air flow
I would do as @raustin mentioned and Remove mold slowly and turn fans off while doing it
If you can remove the pot from tent that would be best
If it returns i would repot the plants
Whats the humidity in grow space
Do you have a exhaust fan running? Or intake fan


I do it 1:4 with bleach. You don’t need a lot.

They make a product called Green Cleaner that you could use. My buddy swears by it for bugs and mold. I believe u can use it up to flower should be able to get a variety of sizes, here is one link.

Green Cleaner 749804 Home Pest Control Sprayer, 8 oz



@Countryboyjvd1971 I struggled to find something that didn’t include any potential advertising conflicts. But I wanted to post this because I feel like this is a pretty common occurrence in organic grows, and I wasn’t sure if I missing something? Obviously I agree that cutting back on water would help, and it should not be allowed to fester. As posted above. But I also don’t necessarily feel like it’s cause for alarm.

Gardenerd: Organic Edible Gardening | Moldy Soil