Re: CULT: Germination Follow-up

I've generally had such poor outdoor germination every year, that I
would assume it is due to the dramatic fluctuations in temperature
during 'chilling' plus lack of moisture once temperatures warm up.  I'm
not sure, but many of my crosses have been among late bloomers, which
may be inclined to germinate later in the spring?? when it can often be
windy and dry.

It rains a lot during the winter months most years, so lack of leaching
seems unlikely to be a factor here.

Some of the information I read in the seed germination books that I
posted about previously makes me think that warm temperatures after too
short a chilling time may undo the effects of chilling, putting seeds
back into dormancy that may last till the next winter.  Also,
temperatures that are high when seeds are ripening affects dormancy
(makes it harder to break), at least in some species.

In any case, I am certainly getting higher first year germination rates
with controlled soaking and chilling than I was planting outdoors where
both temperature and moisture of potting mix fluctuated widely.

As is reported in Vallette's book, gases (ethylene & maybe CO2) and
humidity enhance germination.  So keeping the seed pots covered with
plastic is supposed to enhance germination.

Temperatures dropped to the teens last night, so yesterday, I added a
few more cola bottles of water to act as heat sinks inside the cold
frame.  I thought the pots looked like they had more seedligns in them
than when I set them out in mid-December.  Sure enough, 20 additional
seeds have germinated.  Two were from the 2 month chill group; the other
18 were from the three month chill group.  That brings the totals to 10
out of 100 seeds in the two month chill group and 78 out of 296 in the
three month chill group.  Three seedlings died.  Several had freeze
damage to the terminal leaf from prior freezes.  Most are about 1.5 to 3
inches tall now with 3 leaves.

The additional germination leaves me wondering if 3 months is a long
enough chill for these crosses, or if they just took longer to
germinate.  I have enough seeds in the fridge now (from the same
crosses) that I can try leaving replicates of a few in for 3 and 4
months, but that will mean the 4 month batch won't come out till April!
Seems a bit late....plus I'm getting tired of handling so many seeds in
different ways!

And then there is the question of what to do with the third of my
crosses that didn't germinate at all........Put them out in the cold
frame for the rest of the winter?  Keep them on the enclosed porch till
spring?  Put them back in the fridge?  And what should I do with the
replicates of those that didn't germinate that are now burritoing in the
fridge?  Chill for 4 months?  Take them out of their burritos and put
them back in the toilet tank?

--
Linda Mann east Tennessee USA zone 7/8
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