MaLiorzh
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Joined: Fri May 18, 2018 8:08 am
Location: Brittany / Breizh / Bretagne 9a

Mold and warm/cold stratifying seeds

I've got seeds that need stratifying before they'll germinate. Some need warm and then cold stratification. I had Canadian wild ginger (Asarum canadense) and Meum (Meum athamanticum) seeds in damp vermiculite in freezer bags in a warm dark spot in the house. All the seeds went moldy within a week and I assume are now dead. What can I do to prevent mold growth other than using clean fresh vermiculite from a newly opened packet?

Vanisle_BC
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Joined: Mon Apr 13, 2015 9:02 pm
Location: Port Alberni, B.C. Canada, Zone 7 (+?)

MaLiorzh I don't know much about this but my guess would be that either the seeds were not viable (both, unlikely?) or didn't like the temperature and rotted before they could germinate. Other folks will have more informed answers. It seems to me that mould itself - on the soil for instance - doesn't usually affect "live" seeds.

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applestar
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Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

Seeds that take long period pre-germination rest period is always tricky. Tiny seeds and low germination seeds, too can be a challenge because they can lose viability quickly if not properly stored, whether by the seed vendor or the gardener.

Smaller the seeds, the more difficult because they can’t be covered too deeply, but will also dry out or can get washed away easily, and any foreign organism could easily overwhelm.

So you ave two options — sow and mostly forget on top of large and deep enough container of reasonably weed-free, biologically stable medium, maybe covered with glass or constantly moistened paper, checking often... or use one of the various naked seeds pre-germination methods. With the latter, sterile medium — whether paper towel, sand, vermiculite, seed starting mix, etc. is a must. And it’s really important to look in on them often to open the bag/cover and ventilate... every day if possible.

If going with the 99.99% mold-free method, start with alcohol cleaned bags, pour boiling water on the medium (or pasteurize or bake, etc. or chemically sterilize) and cool before using, and treat the seeds themselves. But longer the incubation/stratification period, the more chance of stray spores finding their way into the bag or container. It’s often recommended to spray with diluted peroxide solution as preventive. (about be careful if pH is a concern).

Larger seeds are more likely to succeed and start growing when you may have forgotten about them and even start to neglect them. But larger seeds with greater amount of nutrients are also more likely to harbor/nurture mold and other disease.

I will admit that I have had mixed results and have been particularly unsuccessful with fine as dust kind of seeds and surface/light needed to germinate that take longer than 2 weeks unless I sow A LOT of backup seeds.

imafan26
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Location: Hawaii, zone 12a 587 ft elev.

I agree with pasteurization as well as either boiling the water or using distilled water since if your water is also chlorinated, some plants do not like that as well. Warm, dark, and enclosed great for mold. Your media may be to wet and that will rot the seeds.
I have not had luck germinating in enclosed bags. I have had better luck using the grape containers with the holes in the tops. It is a mini greenhouse, it keeps up humidity but does allow air to circulate. It may need some spritzing once in a while, but it does not need much if it is indoors. I keep my container under the bench outdoors so it actually gets regular water.

I am not familiar with that kind of ginger. I only grow tropical gingers like Galangal, edible gingers and some ornamental ones. Since I live in a warm climate the ginger pretty much takes care of itself. Only the Jamaican ginger and curry bloom and go down around November. I only have to harvest and replant. The curry comes back quickly, but the ginger is only starting to grow now. It is late probably because the weather has been cooler than normal.



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