sooby said:

In Dr. Griesbach's study,

Hi Sue,
I think you are a member of the Facebook Daylily Hybridizers Nook. There is currently a survey there that shows what method people are using.

bobjax said:

Hi Sue,
I think you are a member of the Facebook Daylily Hybridizers Nook. There is currently a survey there that shows what method people are using.

No I don't belong to that FB group, the few I do follow are enough and I really don't like the "nesting" format on FB. I know that sometimes people make starting daylily seeds a lot more mysterious and complicated than it needs to be and quite often I think the seeds germinate despite rather than because of that.

bobjax said:

Hi Sue,
I think you are a member of the Facebook Daylily Hybridizers Nook. There is currently a survey there that shows what method people are using.

I had a look at the survey since the Hybridizer's Nook is a public group viewable by non-members and I'm not sure I see what the goal is.

It appears to be asking people what is the first thing they do after they harvest and dry their seeds, but does not address what germination rate they get over what timeframe afterwards, which is the whole point of stratification.

The survey options relate to after harvesting and drying, but what is drying? A few days, a few weeks? That would make a difference. Then two of the options don't seem to fit, why would someone dry seeds and then plant immediately, or stratify immediately, two of the four options? Also what about people whose first step is to dry and store in the fridge, then rehydrate to stratify?

I have to agree with some of the FB comments, there seems to be confusion between stratification and storage in a fridge. Stratification is not "wet storage" (actually should not be "wet" at all, or prolonged, just damp chilling for about 4 weeks). Dry storage (fridge) is just to hold the seeds over so they stay viable for longer periods until people are ready to start or stratify them, it's not intended to break seed dormancy, and it doesn't (disregarding for the moment that seed dormancies can wear off during dry storage).

Edited to clarify that in the last paragraph I was referring to refrigeration.

If a seed has in its genetic history a need to dry up first, and then get wet again with fall rains ( which would occurr naturally in a Mediterranean type climate like mine here in the S.Hemisphere), then it makes sense to dry out seeds of daylilies and rehydrate them later. By now, like it happens with so many highly modified cultivars in roses, irises, true lilies etc. the genetic complexity is enourmous. So it is very difficult to tell apart which option will hold true universally. With such complex backgrounds, extrapolation to universal solutions is too risky. That doesn't mean that a systematic experiment shouldn't be conducted. When it comes around cultivars I would solely accept the validity of results if restricted to the chosen cultivars. The remainder ( which will be thousands) will still remain in the realm of inferred speculation.

Arturo

I'm coming a bit late to this one, but the assumption that stratification is needed is wrong in my experience.

Daylily seeds have a hydrophobic (likely waxy) coating that I think inhibits them from absorbing water. Ever notice how the seeds tend to float because of the surface tension of water? If you scarify the seed (scratching the waxy coating), they absorb water immediately and germinate just as rapidly as cold-moist stored seed according to my experiments. I simply swirled some seed around in a bottle lined with sandpaper to scarify the seed. I used seed from Stella De Oro bee pods, so they were dormant. Both dry scarified and cold-moist stored seed germinated at the same rate (100 seed each) and much faster than the control unscarified dry seed.

I speculate that cold-moist storage either breaks down the coating or results in very gradual absorption of water.

My wax theory could easily be tested by using a solvent for the wax and seeing if that improved germination speed. The solvent could then be analyzed to determine the composition of the wax.

The black coating on daylily seeds is made of phytomelanin, the main purpose of which appears to be to protect the seeds from insects and pathogens (where it has been tested in other plants that is). I've always thought it was unlikely to be impermeable to water because many daylily seeds will germinate within a week or two of planting without any pre-treatment.

Back in the 1950's Griesbach and Voth proposed that the delay in germination of some daylily seeds was due to inhibition of oxygen: "Differential peeling experiments demonstrated that an endosperm membrane one cell thick, which covers the protruding tip of the hypocotyl, was responsible for delayed germination at 22⚬ C., while at 16⚬ C., in addition to the membrane, endosperm storage tissue restricts gaseous diffusion."

From: https://www.journals.uchicago....

Scarification would probably affect that membrane.

I don't think anyone has said that stratification of daylily seeds is "needed" although it likely has been interpreted that way in some cases. Viable seeds with initial seed dormancy will germinate eventually even if they take their own sweet time. The idea is that they "benefit" from stratification, or at least the humans benefit, by speeding things up - that's if the seeds have seed dormancy, which doesn't seem to apply to everyone but few people seem to test their daylily seeds for dormancy by just planting some without pre-treatment as in your test, Mike.

Certainly scarification and also removal of the embryo permits quick germination, I have tried both. The downside to me is that the seeds then lose the phytomelanin protection and are potentially more vulnerable to loss, especially if good sanitation is not practiced.

I sell seeds.
I use the plastic bags with a piece of bleached paper with ID written on it, the bleached paper will turn color, purplish, if mold is present, the seeds have been dried for one to two days.
I store in the crisper, the only reason I do this is to deter premature sprouting, It's hard to sell seeds that have already sprouted when the buyer may not be ready for shipping.
There is no other reason for dry cold storage other than having unsprouted seeds ready for shipping, or prechilling for dormant genetics.
Even then a few of the evergreens will have started in the crisper, so I let buyer decide on shipping or canceling.
I do know that many add water peroxide to seeds when they want them to sprout, I just bury the seeds a half inch deep and let them grow when their ready.

@EdBurton,
What exactly does "pre chilling for dormant genetics" mean?

dormant plant seed need a cold period for best germination percentages, a few months in the crisper of the refrigerator is what I do here.

Ed,
I have recently been involved in some discussions about seed dormancy and stratification. I may become involved in an experiment related to it later. So I want to make sure I am understanding exactly what you are saying because the language can get pretty confusing.
"There is no other reason for dry cold storage other than having unsprouted seeds ready for shipping, or prechilling for dormant genetics." Am I understanding that you use dry cold storage to increase the germination percentages over a certain period of time of seeds that are dormant?
The discussions we are having are about "dry" vs. "moist" seed storage for a period of approximately four weeks in order to break seed dormancy and which will result in a higher more uniform germination rate.

Seedfork said:
The discussions we are having are about "dry" vs. "moist" seed storage for a period of approximately four weeks in order to break seed dormancy and which will result in a higher more uniform germination rate.

My guess is that although the seeds are dried for a day or two, Ed's seeds still contain enough moisture for stratification to work, otherwise there wouldn't be some sprouting in the fridge.

I'm not convinced that seed dormancy and foliage habit are directly connected. When I've started "dormant" x "dormant" seeds without pre-treatment there have always been some that germinated immediately, and they were not likely to have been evergreen. Going back to research in Japan also, they tested seeds from a deciduous species and seeds from an evergreen species and both had some that germinated immediately and some that were delayed unless stratified.

So, is the point of drying seeds before storage mainly to prevent germination? I was thinking it was more to eliminate mold, of course it probably serves both purposes. I guess it does emphasize that the amount of moisture present during cold storage should be considered. It appears very little moisture is required.
I have read that when seeds are dried they shrink, and that when a little moisture is added they plump up. So is the fact that the seeds in the fridge being chilled for stratification purposes swell and become plump a sign they have received enough moisture to break dormancy?

Seedfork said:So, is the point of drying seeds before storage mainly to prevent germination? ......So is the fact that the seeds in the fridge being chilled for stratification purposes swell and become plump a sign they have received enough moisture to break dormancy?

To answer the last question first, I would say no. It would be whenever they have had enough chilling time while sufficiently hydrated, and the time needed for that can vary quite a bit. Three weeks would be the minimum time for stratification to cover most daylily seeds but 4-6 would be safer.

Drying is a difficult question because there are degrees of drying. Unless you are in a very humid environment you do not need to store daylily seeds in a fridge, and they will dry naturally over a couple of weeks or so unless enclosed by something impermeable. Storing in a fridge prolongs viability and yes, people do find they are less likely to mold if they are at least somewhat dried first.
.

I certainly agree that enough chilling time while sufficiently hydrated is needed to break dormancy. But, I am asking does the fact that the seeds go from being dry and shriveled, to fat and plump indicate they have received "sufficient" moisture, it seems generally accepted that a period somewhere between 4-5 weeks is "sufficient" time.

I'm not 100% sure I'm understanding the question properly, but it is possible for them to respond to chilling at less than saturation if I recall correctly from Griesbach's experiments. So you would be counting 4-5 weeks from the first exposure to moisture, e.g. the day you first put them in damp vermiculite or whatever and placed in the fridge.

@Seedfork
" the seeds go from being dry and shriveled, to fat and plump indicate they have received "sufficient" moisture"

As a dried seed starts to absorb water it starts to become larger - to weigh more - to swell. But how large it becomes depends on how much water it has absorbed so far. Presumably, it will continue to absorb water until it reaches a maximum amount.

The figure below is for soy bean seeds. It shows that the seeds increased in weight for many hours and then sprouted. We don't know when they might have been described as fat and plump but it could have been at 10 or 15 hours and the seeds did not sprout until about 47 hours. Nor do we know whether the seeds would have been able to sprout if they had been tested after 10 or 15 hours rather than left to continue to absorb water until 72 hours.

So the question for daylily seeds would be - how plump do they need to be to have received "sufficient moisture". See my post below.

This is what Griesbach wrote about the moisture level of daylily seeds before stratification and the resulting germination levels.
"Stratification at 3.5° C. was equally effective
throughout the range from one-fourth to full saturation
(fig. 13). Germinations of 78, 76, 70, and 72%
were obtained for one-fourth, one-half, three-fourths,
and full saturation, respectively, in contrast with
2% for the lot which had been air-dried before
stratification.

Figure 13

admmad,
Thanks, that is what I was trying to ask. I don't put anything in my little baggie except a spritz of water, the seeds swell
to a nice plump fat seed. I prefer not to have to sort through some growing medium to find the seeds and I like to see the seeds so I can tell if they are sprouting or molding, etc. I am not wanting to plant them in the baggie, just break dormancy.

Thanks to everyone for such great insights.
Last year I did not know about cold damp stratification but my seeds almost all germinated anyway. This year, I tried to do it the 'correct' way but found that leaving damp seeds alone in the fridge for 5 weeks without supervision meant a few got mold and had to be thrown away (including very very expensive ones - maybe my peroxide was off ), versus 1-2 weeks at room temperature where I find that I check them daily so can quickly intervene if anything is amiss.
I am not sure how often you guys check-in on damp seeds in the fridge, but I found that I forgot about them until that date on the calendar pops up to bring them out (out of sight, out of mind ).
So now I am moving to a hybrid model. First trying at room temperature, and only then after 2 weeks putting any remaining non-germinators to the fridge for a month or more as a last resort, before returning them to room temperature again. Or splitting crosses into 2 batches and putting one to the fridge and other to room temp. I do not care if all seeds of the same cross germinate simultaneously or not. I do not see any advantage of having to deal with them all at the same time, anyway. But at least this hybrid way I can be pretty sure I will have some seedlings of expensive crosses that do not perish to mold.

Trying to answer Larry, chilling doesn't increase germination rates, seeds are good or they aren't, I chill to prevent sprouting before I ship.
If I bag seeds and store without drying the bags turn into a wet mess with many seeds rotting or sprouting, I've found that one or two days of air drying works best for most seeds, ripeness of pods determines the drying time for me, some seeds get 3 days, while fall apart ripe pods one day is plenty.
after a few weeks in the fridge I check seeds, if the white paper I use to check for mold will show signs of being soppy wet, those seeds need more drying time.
I don't like to dry to the point of shriveling seeds because it takes longer to germinate and I feel some seeds will never recover, so a little dampness doesn't bother me as long as they don't sprout before I ship.
It's a fine line and not all seeds fit one answer, evergreen seeds seem to be eager to start at first chance I've seen seeds sprout when I leave them by the desk for a day when getting them ready to list, I just started 20 some seeds from the cross of So Beautiful To Me x Viserion, left them out overnight before listing, next day all the seeds were actively growing only solution was planting, dormant take longer and store easier at least for me.