seeds needing cold dormancy?

[Lyn96]

Does anyone know which cold hardy palm seeds need a cold spell in the refrigerator before they'll germinate? It seems like Trachycarpus fortunei  does;  bGermination ecology of Trachycarpus fortunei (Arecaceae), a species with morphophysiological and shoot dormancy
https://www.researchgate.net/publication/351467162_Germination_ecology_of_Trachycarpus_fortunei_Arecaceae_a_species_with_morphophysiological_and_shoot_dormancy

And I'm wondering particularly about Chamaerops humilis and Chamaerops humilis var. cerifera, but am also curious about any other hardy palms.

BTW, I thought it was fascinating to learn from that study that many many palm seeds' ovaries do not mature by the time the seed is ripe on the tree and some will only mature after a cold spell. Others seem to stop developing and go back into dormancy if it's too hot.

[bruce Steele]

Here is an old post on stratification.

[Fusca]

@Lyn96

The only palm seeds that I have successfully germinated after cold stratification are Butia odorata and Trachycarpus fortunei.  Like Dick Douglas mentioned in the posted thread Rhapidophyllum and Trithrinax are good candidates.  Jubaea and Parajubaea might be as well.  Chamaerops?  It probably wouldn't hurt to try.  If you have a chance to test it let us know the results.  I've never had problems germinating Chamaerops without cold stratification.  I would say that it might help speed up germination for certain species but it's certainly not needed.

Edited February 14, 2023 by Fusca

[Las Palmas Norte]

I would harvest T. fortunei seed in the late winter or early spring after they'd stayed on the trees over winter. That could probably be said of numerous cold hardy types of palms.

[Lyn96]

On 2/13/2023 at 5:04 PM, bruce Steele said:

Here is an old post on stratification.

Thank you! That answers another question I had as to how long. One study used 3 months cold stratification on some seeds, maybe the T.f. one. I planned on 4 weeks as 3 months would be a PITA.

I'm finding a lot of studies that seem to indicate that the moisture content of seeds might be more important in most varieties- too dry and they die. Also read one that found less germination for longer times soaking in water. The authors of that study wondered if the poor germination rate with  longer soaking was because of lack of oxygen for 5 days. Which would make sense if the seeds are still in the process of developing the ovaries.

[Lyn96]

On 2/13/2023 at 5:52 PM, Fusca said:

@Lyn96

The only palm seeds that I have successfully germinated after cold stratification are Butia odorata and Trachycarpus fortunei.  Like Dick Douglas mentioned in the posted thread Rhapidophyllum and Trithrinax are good candidates.  Jubaea and Parajubaea might be as well.  Chamaerops?  It probably wouldn't hurt to try.  If you have a chance to test it let us know the results.  I've never had problems germinating Chamaerops without cold stratification.  I would say that it might help speed up germination for certain species but it's certainly not needed.

Thank you. Yes, I will. I'll probably only stratify for 4 weeks as longer would be a major PITA for me. The T.F. seeds I got came with 10 free sprouted ones, so hopefully they're from the same plant and have already been stratified.. That study stratified I think for 3 months..

[N8ALLRIGHT]

This thread spurred me to cold stratify some seeds I've had sitting in moist perlite for months. 

Needle 8 months

Princeps 6 months

Princeps x waggie 6 months

Butia 4 months

Needle from Bigfish, Trachys from Victor Silver and butia collected by me. Pretty confident in the seeds viability and these all seem to be good candidates for this, going to give them 6 weeks and then community pot them since we're heading into the warm season 

[Lyn96]

On 2/13/2023 at 5:52 PM, Fusca said:

@Lyn96

The only palm seeds that I have successfully germinated after cold stratification are Butia odorata and Trachycarpus fortunei.  Like Dick Douglas mentioned in the posted thread Rhapidophyllum and Trithrinax are good candidates.  Jubaea and Parajubaea might be as well.  Chamaerops?  It probably wouldn't hurt to try.  If you have a chance to test it let us know the results.  I've never had problems germinating Chamaerops without cold stratification.  I would say that it might help speed up germination for certain species but it's certainly not needed.

Actually I'll take back that "will do" I responded earlier. I forgot my refrigerator is outside and the temps in it occasionally go below freezing.. I have to bring them inside when that might happen. I'll do the best I can with forecasted weather.. But it won't be scientific by any means.

[Lyn96]

On 2/15/2023 at 3:38 PM, Lyn96 said:

Thank you. Yes, I will. I'll probably only stratify for 4 weeks as longer would be a major PITA for me. The T.F. seeds I got came with 10 free sprouted ones, so hopefully they're from the same plant and have already been stratified.. That study stratified I think for 3 months..

Actually I'll take back that "will do" I responded earlier. I forgot my refrigerator is outside and the temps in it occasionally go below freezing.. I have to bring them inside when that might happen. I'll do the best I can with forecasted weather.. But it won't be scientific by any means.

[Lyn96]

On 2/13/2023 at 5:04 PM, bruce Steele said:

Here is an old post on stratification.

Wow!

While re-reading that old post I found; (PalmGuyWC)"I once had some Rhapidophyllum seeds and some I planted fresh, and the others I stratified in moist sand for a couple of months. The untreated seeds took over a year to germinate and the stratified seeds started germinating in two months, and in a much more uniform way."

This makes me wonder if it does NOT require 3 months of stratification, but only that the embryo starts to develop more after some X amount of time (per species?? 2 months?? ) of colder temps and it takes a total of 3 months or more between stratification and embryo development. Because the embryo keeps developing after the seed is "ripe" and picked off the tree. Does stratification induce further embryo development? Seems like it. I would also think if it's too cold (or warm/hot?) while the embryo is actively developing it would slow or pause development and so slow germination. Goldilocks temps after 1 - 2 month maybe. Depending on species. Maybe a slightly cooler temp..??

Plus... IDK. What if the seed someone buys is already inadvertently stratified- picked off the palm after a couple months of cold or left in someone's garage or a cold warehouse for a few months before selling? Then, what would an additional stratification do??

Edited February 20, 2023 by Lyn96
emphasis

[Bennz]

I just found this thread, and the link to my 2007 post. Earlier this year I found another germinated Parajubaea seed in the communal bag (still a few left) from my importation in 1999. So that's 24 years after seed collection!

[Fusca]

24 minutes ago, Bennz said:

I just found this thread, and the link to my 2007 post. Earlier this year I found another germinated Parajubaea seed in the communal bag (still a few left) from my importation in 1999. So that's 24 years after seed collection!

Wow!  Another example of not giving up too soon!  Patience is key in the seed germination game...

[ChicagoPalma]

You can also germinate T. Fortunei seeds and other seeds without stratification, although mine probably got a week of stratification in the amazon prime truck, lol. But while they might take longer, it really just depends. You could possibly have a stratified seed for a week and still get the same results as a stratified seed for 4 weeks. Either way I forgot to stratify my T. Fortunei seeds, but they still should grow. 

[N8ALLRIGHT]

Butia, princeps, princeps x waggie and needle all got community pot treatment after almost 2 months in the fridge 🤞 With any luck my next update will be pic's of sprouts. 

[N8ALLRIGHT]

Not sure if it was the stratification or not but we're starting to pop waggie x princeps and princeps. No sign yet from the butia or needle

[N8ALLRIGHT]

Needle from @Bigfish have shown up, now for the butia! Princeps and waggie x princeps cross moving right along as well

[Bigfish]

1 hour ago, N8ALLRIGHT said:

Needle from @Bigfish have shown up, now for the butia! Princeps and waggie x princeps cross moving right along as well

The Needles are popping here as well, but they are slooooow, lol.  Nice to see that!