Oh, No! I have mold! Help!

Litchfield, IL

All of my seedlings have been doing so well. I have transplanted many into 3 0r 4 inch pots. I also made some mistakes I've found. I put some of my pod seedlings into rectangular 10 cup peat pots. I put the long peat pods into the plastic trays. 5 across. Well now I see that many of them have a white moldy growth on outside of pots. I am sure I must have watered them too much as they are a mess. And they were doing so well!! I know I read somewhere about using peroxide solution but I need instructions. I have begun to take the seedlings out of those pots and put them in others but stopped because I wasn't sure what to do and I don't want to loose them.. If I knew how to attach pictures I would do so.

Thanks for any help for this beginner!

Everett, WA(Zone 8a)

I'm not sure that mold can be "cured": most people talk about prevention. On the other hand, if the mold is only on the pots, and not on the stems, you might be lucky.

I have heard many people say they use peroxide stronger than this, but I've stayed on the "weak" side because I only use it for soaking seeds, not fighting fungus or mold. This site suggests 0.2% for sick or fungusy plants. Since you'll be spraying sides of peat pots, maybe you can go much stronger.


I assume you are starting with normal 3% "drugstore" peroxide (not the 35% food grade stuff).

1 cup water + 1 tablespoon of 3% HYDROGEN PEROXIDE
1 pint water + 2 tablespoons of 3% HYDROGEN PEROXIDE
1 quart water + 1/4 cup of 3% HYDROGEN PEROXIDE
1 gallon water + 1 cup of 3% HYDROGEN PEROXIDE

Litchfield, IL

Thanks so much. So far the mold seems to be on the outside of pots. Can I spray the plants with this peroxide mixture as well?

Everett, WA(Zone 8a)

Stuff that dilute, sure. I've read many people talk about spraying seedlings with stronger peroxide, so this dilute stuff must be harmless.

I've only used it a few times and see no effect on plants. Pre-soaking seeds in a half-strength version does seem to make some old seeds sprout faster - I can't prove it but I do believe it.

Maybe a fan would keep the outsides of your peat pots a little drier and discourage the mold. Of course the pots and plants would dry out faster also.

I always use plastic pots or trays with cells since I tried a toilet-paper-roll collar around something and the cardboard became covered with white mold or fungus. Yuck!

Litchfield, IL

Yep that white mold or fungus is what I'm dealing with. Yucky for sure. My granddaughter and I peeled the little yucky pots off and repotted for hours today. I'll know better next year, I hope.

Durhamville, NY(Zone 5b)

I detest peat pots for just this reason. They are either too dry or mold.

Eastlake, OH(Zone 5a)

I agree with Rick, I use only plastic trays and plastic inserts. When the plants need transplanting, I use a clean tray and new deeper insert, to allow the plant room to grow. I through out the inserts, but use trays over after sterilizing with bleach and warm water. Air circulation is very important. I use fans for air circulation and to toughen the plants.

"Stay Happy and Keep Gardening"

Chino Valley, AZ(Zone 7a)

DH is a big yogurt eater so I save all the empty individual yogurt cups and use them as pots. I just use a hot soldering iron to make a hole in the bottom for drainage. Depending on the size needed you can use dixie cups, empty medicine dispensing cups, and if someone is doing a food demo in your local Sam's or Costco just ask if you can have the empty plastic cups for seed starts. I use them all the time to set down cuttings and African Violet leaves. I haven't had good results with peat pots and the few that my mother gave me are headed for the trash can.

Anderson, IN(Zone 6a)

After I posted this earlier , I read through this , Here's my 2 cents input .
Sometimes mold is not mold , it is the peat fiber trying to regenerate ,, (it could be argued moss is a mold ) however ,, presoaking and setting peat pots in a tray can sometimes help .
The half of the picture closest to you and what it is farther away and green ,, This happens a lot with moss and it will take a lot more light in humidity than most will have thought about (previously myself also ) ..
Well anyway the picture ,,

Thumbnail by juhur7

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