Bonsai - Cold Stratification

My Jack Pine Bonsai seeds came in today. The directions say it needs 8 weeks cold stratification to germ. I did a little reading, and it seems pretty straightforward. The seeds need to be in a dark place, below 60F, and moist (not wet) for 2 months. But, I have a feeling if I wrap them in a paper towel and toss em in the fridge for that long, they will just wind up all gnarly and moldy.

Any ideas, tips, tricks, advice would be cool. Thanks.

I wonder maybe soak the seeds for a while and then put them in a sealed small jar (jelly size mason) no medium, if that would work. you got enough try a couple of ways some with medium.

first 6 threads I read they all have different methods

BarnBuster said:

I wonder maybe soak the seeds for a while and then put them in a sealed small jar (jelly size mason) no medium, if that would work. you got enough try a couple of ways some with medium.

first 6 threads I read they all have different methods

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That's a good idea. No medium at all. You would think that would significantly reduce the chances of mold. Gonna try a few that way, a couple in rockwool (which are supposedly sterile), and a solo cup/potting soil with a saran wrap cap.

I guess if all else fails I can just wait for colder weather and pop em in a smart pop out back. Kind of frustrating - I've always read seedlings love warm temps, and that's what I'm prepped for. Never heard of something taking so long to germ before.

Thanks, boss.

didn't I also read you have to heat these up or something as well?

BarnBuster said:

didn't I also read you have to heat these up or something as well?

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You know I am not sure. I need to do some more reading about this strain.

Stratification is cold, moist dormancy. It simulates what the seed would experience if it sat in the leaf litter over the winter. From a botanical point of view, stratification prevents a vulnerable seedling from germinating in the fall because it would have little chance of surviving the winter.

Simply sow the seeds as recommended in a pot or flat and place in the refrigerator. Check every couple of days. When you see the first seed germinate or the recommended number of days has passed, remove the pot and place in full sun in a warm location.

Note that stratification involves "moist" dormancy. Dry seeds do not usually respond to a cold treatment only. There must be moisture.

Nothing to it really. I've stratified hundreds of seeds. It's easy and uncomplicated.

Your idea of putting in the fridge is spot on. Keeping it dry is crucial as moisture will result rotting. Where I live we use stratification for Tulip bulbs we dig them up wash an dry them an keep them in the bottom of the fridge until spring replant them enjoy the flowers allow them to die back repeat. Reason for this is they like to be berried under snow through winter.

The black Pine Comes from Japan an gets covered every year with snow, So in order for them to sprout they need to believe they have been covered in snow for the winter that way they will sprout. Like the Tulips from Holland.

Dont put them in soil in the fridge they WILL rot over that period keep them dry until you plant them

Happy gardening

Claypipe you are conflating stratification, vernalization and seed storage.

Stratification is the process that duplicates the typical overwintering conditions for the seeds of temperate climate plants. Stratification requires cool, moist conditions. Here are two good articles on stratification, note the emphasis on 'moist'. Moisture is required because ultimately we want the seeds to germinate.

http://conifersociety.org/discussion/topic/growing-conifers-from-seed/
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1845&context=extensionhist

Vernalization is the process that duplicates the conditions experienced by a bulb or woody plant over winter. Unlike stratification, additional moisture is usually not necessary.

https://en.wikipedia.org/wiki/Vernalization

Seed storage requires cool, dry conditions. Dry is required because moisture will encourage the seeds to germinate.

http://sbc.ucdavis.edu/About_US/Seed_Biotechnologies/Seed_Storage_Conservation/

I am not confusing anything except the Japanese black pine which is very popular bonsai. I live in the tropics & here if you want to get seeds to sprout or bulbs to flower from cold climate areas, we put them in the crisper of the fridge this is not to sprout them it is to trick them into thinking they have been under very cold ground.If we leave them in the ground over winter they dont get the chill factor. We also get a lot of rain over winter causing them to rot. As the jack pine grows in an area that gets snow over winter. That is why they recommend giving them the chill factor as they dont know where the buyer is going to try an grow them... Good on you for your through correction on my opinion.

Claypipe,
Do temperate climate plants, such as Pinus thunbergii, grow normally ("grow normally" not "normally grow") in your climate or do you have to provide artificial vernalization every year?

No they dont an If you attempt to bring in say a small tree Of the Japanese Black Pine you referring to, an plant it in the ground. It would grow for a few years thoroughly stressing. After about 3 or 4 years it be dead from insect attacks mainly termites an others. To my knowledge it would be impractical to artificial vernalization each year. The temp do not cold enough not even frost ever

Ive propagated pines before in a gh after stratification. 8 wks planted in a peat/perlite/sand medium and heeled in in a cold frame over winter. Worked pretty well
Ive cold stratified Verbena seeds per the package instructions for one month and two months for comparison, panted the same way but put them in a fridge. Worked good.
You'd think they'd get mold but never did.
Plant them first, then chuck em in the fridge. A gallon baggie around the pot will keep it moist.