Molds on rose seeds

One of the ‘benefits’ of germinating roses on paper towels, is the ability to watch the molds grow. Some molds appear to have little effect on the germination of the seeds, and indeed, seem to assist germination. Others appear to be lethal.

I’ve posted some pictures of molds on my seeds and hopefully little by little I will attach info on the molds and how they seem to affect germination. Any info you may have with your experience with these molds would be welcome.



I think I’ve seen many of the same types of molds that you’re getting. They all look familiar.

Anyway, it was especially nice to see the little germinating rose seed in the fifth picture. Hope it’s a nice one for you. I just got my seeds planted, so it’ll be a while before I get to see any sprouts firsthand.

Looking forward to hearing what effect these different molds have on your germinations.

Thanks, Tom

I’ve got about 100 little seedlings so far this season. One of the black molds from last year hasn’t shown up yet and I hope it does because I’d like to get a picture. It seems to encourage germination and not hurt the embryo at all. As a matter of fact, last year I actually took spores and innoculated some other seed batches with that mold. Maybe I have a photo from last year - gotta go look.

Thanks for posting this, Judith. I had seen molds on some of my seeds and was getting ready to toss them, so this is JIT information! :>

I feel so dirty after watching that…

Mold is nastier when you truly get up close and personal…

Maybe I should have rated it XX

I allow molds to form on seeds while in the fridge and rarely have any problem with seed destruction. In fact, I firmly believe that most molds assist in the decomposition of the seed shell and decompose germination inhibitors. I wouldn’t go out of my way to encourage molds, but when they happen, I disregard them.


I’ve said that for years Paul and have tried explaining this very point. Much of the time all the fuss is not only unneccessary. It’s sometimes counterproductive.

That is probably true when you stratify and then plant in soil immediately, but for those of us who can’t do that, we germinate while still in the paper towels and the mold can get seriously out of hand some types killing the seeds. Of course, that’s the downside to using paper towels. The upside is less mess, and much less space required. I can easily deal with 10,000 seeds from 50 different crosses in a small space. The other thing is, one doesn’t need to worry about the top of the soil in flats drying out too quickly before the seeds get a chance to get their roots down deeply - which can be a really big problem in a hot, dry climate.

I wonder if you would have had a mold problem if you had given your seeds and paper towels a little Captan dip beforehand?

Just a thought…

Judith, before my greenhouse, I stratified seeds in paper towels, but didn’t really want them to germinate in them. After the cold period, I put them in flats to germinate. Then transplanted them individually to pots before they developed true leaves. Germinating in flats rather than in paper towels seemed to cut down on fungal related mortality.

Jim Sproul

I recommend sand instead of paper towels.


Mary, I can’t use Captan because I stratify in the home refrigerator.

Jim, I really don’t have room for the flats, which is one of the main reasons I germinate in paper towels. I plant each seedling as it germinates. I toyed with getting a greenhouse, but it is so hot here in the desert, I can’t imagine a greenhouse being of any benefit unless it were air conditioned, which would cost a fortune. Or am I wrong about this?

Henry, I have tried sand, but I don’t find it reduces the molds, it just hides them a bit, and it makes cleaning the seeds off more difficult (if one chooses to go that route). I don’t have much trouble with the roots growing into the paper towels since I check the seeds daily.

I’ve seen most of these molds except the one that looks like tiny coffee grounds. It seems that the slimy molds are not good for germination.

Fabulous photos - thanks for sharing!


I agree with you Gail. I think the slimy ones are nasty guys!

There are a lot of substrates that will work satisfactorily to keep seeds moist during stratification, but what has worked well for me and I keep using is peat. There is variability from batch to batch, but in general there has been reported some antifungal properties to peat which seems to be the case and at least keeps some fungi down. Paper towels have been a mess for me in the past with some mold and even more so having it be nearly impossible to remove germinating seedlings from if there are a lot of root hairs of the seedlings imbedded in the paper. Using peat and not getting it too wet has worked well for me for years. I transplant out of the baggies which saves me space (I have no greenhouse) compared to flats. The dark peat is nice compared to mixes with perlite and vermiculite since I can more easily see the white radicles of newly germinating seedlings. I do not use captan anymore (it seems to stunt seedlings a bit when I have used it- I suppose better stunted than dead from fungi). If I have a seedling that looks a little infected with fungi that I want to save I might water it with a little 3% hydrogen peroxide straight from the bottle and keep the humidity somewhat high with a loose baggie.

Last night I went through the fridge and have a lot of germinating polyantha seedlings ready to pot! Hopefully tonight I’ll get to them. Rot seems to be more of an issue if I let them go too long and don’t get them potted right away.