Robert, I've been stratifying seeds in the fridge for several years &
usually start seeing germination after about 2 months (8 weeks) in the
pink crosses using warm fridge temperature (~45oF). It seems to take
closer to 3 months (12 weeks) for other colors or at colder temperatures.
I haven't done enough experiments to be able to document the differences
(i.e., same crosses, different treatment), but fresh seeds (like you
describe) & unshelled fresh seeds (i.e., still in the pod) don't seem to
sprout any faster than dried ones wrapped in a slightly damp paper
towel. I don't pre-soak dried seeds. Doesn't seem to be necessary.
Tho I do give them a good soaking by lots of watering once they are
Circled tiny little sprouts in the photo are from freshly dried seeds
that were sprouting in the fridge after ~10 weeks at ~ 40oF wrapped in
damp paper towel in a loosely folded plastic baggie. Seeds were dried
for a couple of weeks? Not sure how long - till they were too dry to
mold in an envelope ;-)
Once they start to sprout, it takes a week or two for them to get above
ground - very important to keep pots & seeds cool enough! Below 70oF.
I prefer 60s. Or they will shut down and you may lose them all. Or if
you are lucky, they will just go into dormancy again and take another
cold cycle to sprout. Nearly all of my work is with TB's - from what
Vicki? I think said a few years ago, some of the other bearded iris
seeds may require cooler temps during sprouting - 50s? Not sure.
Now that the first ones have sprouted, I have potted all of them, will
leave them outdoors for more chilling/sprouting (depending on temps that
nature provides), giving them a good soaking with the garden hose every
day. They can take some frost/light freezing, but if it drops below
30oF, I'll bring them indoors, just to be safe. Eventually, as/if it
gets colder, I will move them indoors to the dining room where temps
stay below 65 on the floor in the winter for more sprouting.
As each pot has sprouts start to show above ground, they will be moved
to the sun porch (with AC if it gets much above 70 during the day).
Some of the seeds that were not starting to sprout when I potted them
(i.e., all the non-pink and some of the pink crosses) will start to
sprout after a few weeks out of the fridge. Others may take a second
round of chilling - I haven't experimented to find out how long or how
warm it is between chilling cycles, just have noticed that there is
usually a second flush of sprouting about a month after the first round
has finished and they've had more temps in the 40s.
<12 weeks in the fridge, then take out during the day time to
stimulate the seeds with warmth of the late summer. So far have not seen
any sign of germination Robert>
Donald, like you, I had some fall germination this year. The two
wretched looking bigger seedlings in the photo came up sometime between
early August when I last cleaned up the pots and yesterday, when I
noticed them. I had one seedling germinate in July a few years back.
Wish I had made an effort to keep track of which one that was! Not sure
what to make of it. My thought is that some genetic mixes aren't as
temperature sensitive as others.?
Linda Mann east TN USA zone 7