What are you using to retard mold?

We are about to update the Handbook for Beginners for the next reprint.

When seeds are refrigerated in a wet Bounty papertowel, in the past we recommended using Captan to retard mold.

Since it is no longer available, what is the popular product that hybridizers are using now?

Captan is no longer available?

Well, I soak in H2O2 for 24 hours before putting the seeds in H2O2 soaked paper towels. I get very little mold on the paper towels, but I do, fairly often, get too much mold on the seeds. If the seeds mold badly, they get re-soaked. If they still mold, I discovered that a 24 hour Oxyclean treatment: about 1/4 teaspoon to 1 oz of water, works much better than peroxide. I would never use toxic chemicals in a home refrigerator.

??? I have not been notified that the update is going forward.

The last information that I have received is in the following thread:


Link: www.rosehybridizers.org/forum/message.php?topid=239#256

Im trying coffee filters this time instead of peat (experiment). I honestly wouldnt use paper towels. Last year I used small amounts of peat into these cool miniature tupperware containers that I poked holes into for air exchange. They worked just perfect. The only issue is that some seeds blend into the peat since theyre both earth tones. So Im trying to coffee filters inside the containers this year. No mold yet. Some are only one month in, though.

I agree about not using paper towels. They are much more prone to mold than peat moss. Coir might work too, although I haven’t tried it.

I seriously haven’t had much of a problem with mold on the Bounty paper towels soaked in H2O2. I do have problems with molds on the seeds with the paper towel method, but maybe only about 10% of the time has the mold actually originated on the paper towels. Usually the paper towels are a secondary infection.

I don’t believe in trying to prevent mold growth on the achenes while in startification. Why? Because I don’t allow the seeds to germinate in the fridge, and so damage from the mold is not an issue. (I do believe molds assist in the breakdown of the seed coat, assisting in the germination process) I find that if I am going to handle 5000 germinating seeds, there is no way I want to have to handle them direct from the fridge to pots; thats too much work, and so I germinate them in flats like most of the big growers do. The seeds are collected in October (generally. I have only a few left to collect now) and put in the fridge on and off for the next 6 weeks. They seeds are NOT removed from the hips at this stage. I remove and clean the seeds in December and put them back in bags with damp paper towel. Why remove the seeds so late? Because the germination inhibitors in the hip flesh continues to prevent early germination. I don’t want seeds germinating until AFTER I have planted them in early March, and I find that two to two and a half months is about the maximum that I can expect seeds to remain dormant after removal from hips.

By all means choose the method that works for you. I am simply offering the details of my own approach and the reasons for my technique. I get very good results with most seed batches, often getting close to 100% germination with most crosses. Definitely a case of “if it ain’t broke don’t fix it”. :wink:


The link below gives my present germination method. I have had to downsize my operation. I no longer use periods of alternating cool and warm stratification but just keep the rose seeds at about 50 degrees F. It was my intention to try replacing stratification with continuous exposure to red light. The red light was produced by using high intensity Radio Shack red light emitting diodes in the constant temperature unit (a half size freezer).


This method gave me as many sprouts as I could handle this past winter. A change that I will probably make for this coming season is to start the process at the end of January instead of the end of December as the seeds starting sprouting on January 11 ( http://home.neo.rr.com/kuska/2003-2004%20seeds%20germinated.htm ).

When spring arrived, I had some very large seedlings under lights, and it was still too cold to start planting them out.

Link: home.neo.rr.com/kuska/new%20germination%20method.htm

So much depends on space, time, and growing conditions. For me, the baggie method works best. If I had a greenhouse or large area for flats, I would probably switch methods, as I agree with you, Paul about the molds. Something is going to have to ‘give’ this year, since I have about 11,000 seeds stratifying right now!

As for damping off, I found that gently rubbing the newly germinated seedling stem with a bubble of straight 3% peroxide on a syringe or dropper works great. On the other hand if you have thousands of seedlings, that method obviously would be too cumbersome.

I think it was Henry that found some soils with mycchorizae that might be good to try. Henry did you ever follow up on that? I have tried to get Pro-Mix FPX with

Bio-fungicide, but have not been able to obtain any because they will only sell it with a minimum 6 pallets!

Judith, I started using the the following when planting out:

(I posted the following in an earlier thread:)

"One of our local nurseries has the orange 4 ounce packets of Roots 1-step available at $2.99 each, regular price - not sale price (I did a web search and found one internet source that was selling the packets at $5.99 each).


I have stopped using Captan altogether even though I still have some. For me, the Brawny paper towels have held together better than the Bounty. I just moisten them in regular water, squeeze out the excess, and put the damp paper towel in a zip-lock bag. I also agree with Paul, it is much better to germinate seeds in soil, rather than in a paper towel in the refrigerator. It is very frustrating trying to untangle roots growing through paper towels!

Jim Sproul

In plastic zip lock bags I recommend sand instead of paper towels.