HYB: TB: germination temperatures
- Subject: HYB: TB: germination temperatures
- From: L* M*
- Date: Fri, 19 Jul 2002 15:21:18 -0400
I spent some time last night rummaging around in the archives and on the
web for details on optimal germination temperatures for bearded iris
seeds. I will edit some more of what I found and post later but the
following temperatures and temperature regimes were found. The note by
David Victor near the end of these (as well as the recent post noting
that some crosses germinated better from fresh seeds than others) makes
me wonder if different genetic mixes of various species contributing to
modern TBs might make different crosses have somewhat different
requirements (variegata, pallida, aphylla, reichenbachii/balkan, etc)
(also rapid 'perennial growers' vs those with seasonal growth) . Soil
temperatures in pots in the coolest part of my yard is reaching nearly
80 during the day & not below 70 at night, probably inducing permanent
dormancy, if not death :-(
--------------
seeds have germinated with soil temperatures ranging from 40 to 60
degrees. Vicki Craig
----------------
The temperature in the frig is around 40 degrees F. Some seed will
begin to germinate Robert Turley Lake Charles, LA
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Bearded irises germinate best at 55 degrees F. John Coble and Bob Bauer
-----------------
I've had seedlings come up and survive with temps as low as 24 degrees.
Rick Tasco
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I. barbuta [modern TBs?] Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to
-4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for
germination
---------------------
just about each and every species has its own optimum germination method
and that it is dangerous to draw general conclusions for other species
from the results for a particular species. For example, I. tectorum
germinates best in light at 70, I. ruthenica was better in the dark at
70 and I. innominata is best at 40. Some perform best after dry storage
of the seed, others not. David Victor
---------------------
Some generalizations from an article by Paul Black: There are several
requirements that must be met in one way or another for bearded iris
seeds to germinate. The first is that there needs to be a period of
chilling lasting at least six weeks with temperatures being below 40
degrees F. The other is that the dormancy factor in the seeds needs to
be leached away with a quantity of water after they are planted. The
endosperm must be hydrated to be able to germinate. The seed must have
oxygen in order to germinate. The chilling requirement is easily met
here since we certainly have at least six weeks when it goes below 40
degrees.
------------------
--
Linda Mann east Tennessee USA zone 7/8
American Iris Society web site <http://www.irises.org>
iris-talk/Mallorn archives: <http://www.hort.net/lists/iris-talk/>
iris-photos/Mallorn archives: <http://www.hort.net/lists/iris-photos/>
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