I mail out a lot of seeds over the Winter months---some to people who are experiencing very cold temps.. So---a few years ago I did a test to see if freezing seeds made any difference. The results were a bit mixed from what I expected---but did give some good advice: 1) Seeds that were from EVR crosses tended to have somewhat less germination rates, but not a big difference from Sev's. It was a bit better with Dor crosses. 2) A more significant difference was seen with seeds that were more moist than others. The drier the seeds, the better they withstood freezing temps. 3) temperature variation made a bit of a difference: some seeds were placed in my 5 cu. ft. freezer and remained there till it was time to take them out and attempt germination. a smaller batch were placed in the freezer in our kitchen refrig.. The latter ones experienced a thaw due to mechanical problems that lasted a couple of days. They were then, again, frozen. There was a 5% difference in germination rates that favored the ones that had not been thawed. CONCLUSIONS: 1) I store my seeds with a bit of moisture in the baggies (but not enough to cause germination to begin). It keeps them plumper, and improves overall germination. However, before I ship them---if they are going to a place where I know the temps are pretty low---I will let the seeds dry out some before they are shipped. If there is more water in the baggy to dry properly, I will repackage the seeds into a fresh baggy with a redone, dry paper label. 2) If there are a lot of Evr x Evr, or Evr x Sev crosses in the shipment I will monitor the weather for that area and ship when I figure the temps will moderate some. Those seeds are usually going to more Southern destinations (USDA zones 7+) so that is not hard to do. I have been shipping shipping seeds for 15+ tears now with few problems---even though I know that some have sat in unheated mailboxes waithg for their new owners to get home from work. There have only been a few instances of germination failure (<50%) reported. Those were mostly due to the crosses (Evr/Sev x Evr/Sev) coupled with unexpected colder weather in the receiving area. Those were a long time ago since weather prediction has vastly improved (believe it or not) with the use of weather satellites and better science due to research. Daylily seeds are pretty durable, and can take freezing as long as they are pretty dry. For those who plant outside in the Spring, it is best to wait for planting to a time near the average last freeze date for your area.
http://www.intellicast.com/Nat... My final conclusion is that the closer seeds get to germination, the lower the chance for germination. Once that initial root cracks the hull and shows, the germination rate plummets if they experience freezing.
