Sanitizing seeds / growing media with Peroxide?

I recall reading something about sanitizing seeds and or growing media with Peroxide. I have had issues with seeds getting moldy in cold stratification and cuttings damping off. I would like instructions from anyone how has had success with that method.

I’d like to hear anyone with experience as well. I grow a lot of trees from seed/nuts and here is what I know:

First, mold comes from mold spores, so the battle starts with collection. I’ve grown a lot of chestnuts which are especially susceptible to mold because of the high carb content. When nuts are collected directly from the husks they have the least chance of exposure to mold or mold spores. When they fall from the husks and sit on the ground for any length of time the chances of exposure go up and the longer they sit the greater the chances. There is also a climate factor. Warm, damp conditions allow for a faster spread of mold. When nuts are just jumped in a bucket, mold can transfer from nut to nut quickly.

Unless you collect the nuts or seeds yourself, you never really know the conditions before you got them. Some folks soak nuts in a 10% bleach solution. I have not seen any benefit from this and with chestnuts, it can have a negative effect. I found there is some acid-base reaction between the shell and bleach. One year when I was dealing with mold issue and washing each nut individually in a weak bleach solution, the hair was burned off my knuckles. I found no improvement in germination rates when I used bleach.

I like to rinse nuts under running water when I receive them to minimize chances of transfer from nut to nut rather than soaking them in a big bowl.

Cold stratification will slow as the water content of the nut drops. If the water content gets to low, cold stratification stops and the nuts kind of go in to suspended animation. However, dampness is also a contributor to the spread of mold. So, getting the right amount of moisture in the Ziploc bag is important. I like to use long-fiber sphagnum, not the short fiber stuff you find in bales. You can use the dried stuff, but I prefer the live sphagnum. It has some natural anti-fungal properties but is not a cure all. I soak it and then make a tight fist to squeeze all of the water out I can. This gives me about the right amount of moisture. Another precaution I take is not to put all of my nuts in one bag. This helps reduce the chances of mold spreading to all the nuts.

However, you can take all the precautions, but if mold exposure occurs at the source, you can still have mold issues. One year, I got chestnuts from 2 different sources. I treated both exactly the same. The one batch had almost zero mold and the other had over 85% with mold issues.

Not all seeds and nuts are as susceptible to mold as chestnuts, so they make a good example. I use best practices from chestnuts to apply to all my seeds even if they are less susceptible.

I have also tried antifungal chemicals to pretreat nuts. They may slow the spread of mold a bit, but once exposed, they don’t seem to stop it.

I also find that I have better success either keeping nuts in cold stratification until a root radicle appears or just planting them after the minimum cold stratification period is over. I find that planting them below the medium rather than setting them on top (which you can do with chestnuts) reduces chances of nuts developing mold.

Looking forward to hearing from folks who improve germination rates and reduce mold with peroxide or any other approach.

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When I use the paper towel method to sprout seeds I use distilled water with a little Peroxide in it and have better results than when I used plain water. much less mold issues and H2O2 actually helps some seeds sprout.

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Starting vegetable seeds, I add peroxide to the water to prevent mold and damping-off