Prolonged stratification

[normando]

So im stratifying some sarrecenia and temperate drosera seeds in LFS in plastic sandwich baggies in the fridge. I put them in on 11/26/12 and its been a couple days past a month now and my question is. Is there a diminishing point of "no return". Can you d harm by stratfying too long? I plan on potting them up soon and pt them under florecent lights to iv em a eadstart before spring but I have no room untill a bunch of my subtropical drosera get big enouf to transplant making more room for the new sarrecenia seeds coming in. So would it be ok to take the seeds out of the fridge aound say, Jan 16th or so? About 6 or 7 weeks of fridge stratification? Thank you for your time and any info provided. Normando

[ICPS-bob]

Here is what the famous Barry Rice says in his FAQ:
www.sarracenia.com/faq/faq3160.html

About four weeks is the optimal stratification time for most Sarracenia. Shorter stratification periods will result in less complete germination. Longer stratification periods for S. leucophylla can result in smaller germination rates. Some Sarracenia may do better with a stratification of about six weeks; S. purpurea var. venosa, S. purpurea subsp. purpurea, and S. jonesii respond to this treatment by germinating faster, although the same overall germination rate is ultimately the same.

Aaron Ellison stratified Sarracenia seeds of different species and locations for 2, 4, and 5 weeks and discusses germination rates.
www.amjbot.org/content/88/3/429.full.pdf+html

[Aidan]

Dec 30, 2012 16:39:08 GMT normando said:

Can you d harm by stratfying too long?

I stratify Sarracenia seed 'naturally' by letting it experience our UK winter and have on several occasions seen a second flush of germination in the second year. Our winters are more severe than most species would experience in habitat but one winter may apparently be insufficient to always break seed dormancy.

[adamcross]

Stratification is meant to mimic the conditions naturally experienced by seeds, informing them when the environment is optimal for germination to occur. Cold stratification obviously primes seeds to germinate when cooler temperatures are replaced by more favourable warmer weather, in conjunction with adequate moisture levels. The current scientific thought is that seeds should be allowed to experience stratification at a length and temperature as similar as possible to those that would be naturally occurring- around 12 weeks in most climates, and usually below 10ºC. Germination is then cued by increasing temperatures in conjunction with adequate moisture and other factors such as fire-related compounds.

Stratifying seeds for longer or shorter periods can harm the development of the embryo, or induce secondary dormancy in some species. Generally the seeds will not be killed, but they may require another season's cycle before they are ready to germinate again. Many seeds will naturally lie in soil seed banks for several years before germinating, waiting for conditions to be completely optimal- sadly many growers lack patience and will claim seeds that do not germinate immediately are inviable!

[paulbarden]

I once unintentionally stratified several lots of Sarracenia seed for nine months and still got excellent germination. YMMV, of course.

[normando]

Thabks to all of you for the great advice! Im going to get things going since this is my first go at stratification and dont want to mess things up. Im actually experimenting with several methods to see what works best. So iv got several outside to strat naturally but im afraid that our winter will be too mild but we'll see! Thanks again guys!