Challenges with Mold in seedlings

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Rapscallion
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Joined: Wed Aug 10, 2022 12:11 am

Challenges with Mold in seedlings

Post by Rapscallion »

Hi! I'm a new grower and have been trying to grow from seed with some success (almost at the 2 month mark!) but have been constantly battling with mold spots developing on my soil.

The lids are off, they're under grow lights for 12 hours, and I've increased ventilation (fan blows directly over the area for about an hour every day). I've been trying to treat with a sulfur fungicide and spot-treating with isopropyl alcohol but not having much luck... the seedlings have been ok so far due to my vigilance, but any advice on how to solve this problem? Is there a stronger fungicide I could be using? I sterilized my soil before planting (4 min microwave), but could this be an ongoing contamination issue/should I attempt to transfer them into clean pots?
Thanks so much
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Aiko
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Joined: Mon Jan 24, 2011 5:26 pm
Location: the Netherlands

Re: Challenges with Mold in seedlings

Post by Aiko »

Are we really talking about mold, or algae? Algae is not a problem.

I usually cook my soil thoroughly. In a pan, on a fire, for a long time. I can't judge if 4 minutes in the microwave is too short or not, but why not longer? And was the soil moist when you were cooking it? Cooking dry soil is probably not very useful, I suspect.
Rapscallion
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Joined: Wed Aug 10, 2022 12:11 am

Re: Challenges with Mold in seedlings

Post by Rapscallion »

I'm pretty sure its mold (or fungus?). There are two different types are showing up, the first cobweb-like and gray-white, and then some bright white fuzzy spots are starting to show up in the echeveria trays.
The soil was moist when I microwaved it, not sure about the time; I think the online guide I looked at recommended that long!
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MrXeric
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Joined: Sun Nov 15, 2020 10:31 pm
Location: California, USDA zone 10a

Re: Challenges with Mold in seedlings

Post by MrXeric »

I've transplanted very young seedlings before and most were ok, but expect to lose some of them. Spraying with a 50:50 solution of water and hydrogen peroxide (the normal 3% stuff) has helped me control the odd pot with fungus and the like. I would scoop out the substrate with visible fungus before spraying. It'll also help if you let the surface of the substrate dry before watering again.
keith
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Joined: Wed Jun 12, 2013 3:50 am
Location: S. CA USA

Re: Challenges with Mold in seedlings

Post by keith »

Mold I move seedlings to drier air and more sunlight it stunts growth of the seedlings but also the mold. I use hydrogen peroxide, pysan20 soil and and on seeds themselves , root tone fungicide, and microwave soil but some pots get mold. Its just the way it is for me.

evenly moist not wet that's the key. hard to do some people put the whole thing in a baggie to keep evenly moist
Rapscallion
Posts: 3
Joined: Wed Aug 10, 2022 12:11 am

Re: Challenges with Mold in seedlings

Post by Rapscallion »

Thanks so much! I'll try the hydrogen peroxide before attempting to transplant them. Here's hoping
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