Re:HYB: germination experiments/cold climate

The anti germination compound is Ascorbic Acid , short form ABS. This
increases 100 fold as seeds are drying out. It has the effect of
stopping any biological activity and thus protects the seeds. In iris
it requires a great deal of moisture to wash it out of the seeds to
permit germination.  Washing seeds in about five soaks in water for
about 1 day each  should remove all the ABS. Some experiments with
planting fresh iris seed before  they dry out, has resulted in good
germination without any cold periods. By planting before they dry out,
they are planted before the formation of ABS.

The need for vernalization  seems to be about 90-120 days in fridge at
temperatures between 38-42F. Some literature I have just read suggest
optimum vernalization  to be between 41-45F and from 12-15 weeks.
Probably the same for seeds.

After the five washes there may not be the need for the vernalization.
Seven weeks would seem to be equivalent to two winters.

A warm period  during the vernalization breaks the period and would
require a restart. One would not likely be enough but several days
would stop it. I have experienced this myself by holding planted seeds
in unheated green house.  Several periods of near 80F  days resulted in
much reduced germination. Best germination is when I keep seeds in cold
room inside attached garage, where I have a heater that runs only to
prevent freezing and temps are from 38-50F. Excellent germination after
3-4 months there

Days of freezing temperature doesn't count in vernalization , has to
above freezing to allow for biological activity. The freezing days just
donbt count in total, but donbt harm seeds.

As I keep temperature records I could check, but most likely between
fall and spring. there would be  at least 90 days of  vernalization
temps .  Experiments indicate that even temps as high as 68F can be
used in vernalization with some plants.

My records have been kept for a bout 5 years, Minimum, Maximum of both
air and ground, but  only one year made it into computer records.

Chuck Chapman





Date: Thu, 21 Feb 2008 06:54:54 -0500
From: Linda Mann <lmann@lock-net.com>
Subject: [iris] HYB: germination experiments/cold climate

After leaving ungerminated seeds in the fridge another month (after a
day every other week at room temperature), I gave up on any more seeds
germinating this winter.

But as I was planting them in pots to spend the rest of the winter
outdoors (unlikely to get below low 20s F the rest of this spring), I
noticed several seeds <finally> starting to germinate in one more cross.

7 months of chilling to germinate?  Could 7 continuous months of
chilling be equivalent to two winters of 3 1/2 months?

Or were those few days in between at room temperature enough to fool
those stubborn seeds!

Chuck, others in cold climates, how many months do you have outdoor low
temperatures below 40oF (4oC)?  (? do seed temperatures below freezing
count?)

 --
Linda Mann east Tennessee USA zone 7/8



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