Linda, you are a hard sell, and I welcome that as it keeps me on my
There is a difference between time needed for chilling to do it's thing
and number of times you need to do chilling.
The number of times has nothing (as far as I know) with how long each
chilling period is. Except that if seed inhibitors are not removed,
for what ever reason, the additional time could result in more
efficient removal of seed inhibitors. So if all seed inhibitors are
efficiently removed through soaking and rinsing, then it would
certainly appear that only two months of chilling is needed.
Before soaking and rinsing, I would have low germination rates and a
fairly high rate of second year germination. With soaking and rinsing
the first year germination is much higher. I suspect second year
germination will be much lower (it has to be based on less seeds
carrying through second winter) even based on number of seeds going
through second winter.
You have to keep in mind that removal of seed germination inhibitors
and chilling are two separate processes, and basically independent.
They would sem to be connected. Iif you just plant seeds and look at
germination results. And old studies didn't use soaking and rinsing.
Just planting, chilling, and looking at results. We now know for
certain that there is a seed inhibiting chemical that can be removed by
soaking and rinsing, so ther
e is indeed a need to relook at how much
chilling is necessary.
My figure of two months is based on observations, so you are right that
it need to be put to the test. The test that would work is using same
crosses (or species seed) do soaking and rinsing, and then have one
batch chilled for two months and one batch chilled for three months. I
can't see going more then that as after three months they germinate in
the fridge (chilling environment).
The recommendation for 4 months, I'm willing to bet did not involve
soaked and rinsed seeds and/or involved using a non regulated
environment, ie: outdoors. In an outdoor environment, four months of
winter probably provides less chilling hours then two months in a
controlled environment, such as a fridge or cold room. This is because
chilling hours are less effective at temperatures below 2C and
basically don't count below -1C. You may need even less the two months
if you use a higher temperature, ie: 8C, but this would need to be
Posted by: "Linda Mann"
Sun Aug 23, 2009 5:05 pm (PDT)
Chuck, your comment about only needing two months of chilling for
seeds seems to contradict a lot of what I'
ve read of other people's
experiences planting seeds outdoors in climates where they certainly
more than 2 months chilling in the first winter.
Including seeds I've planted outdoors before I started burrito'ing.
Don Spoon recommends 4 months.
Joe Ghio had unintentional second year germination that included
STARRING. No idea how much chilling the first winter provides in his
Mohr did some experiments in a greenhouse in Kentucky cycling thru
repeated chilling and germination temperatures and got additional
germination after each additional cycle. I think he told me it was
published in the Bulletin - maybe in the 70s?
I'm not going to be convinced that 2 months is enough for all crosses
until someone does some controlled experiments in pots of soil using
some of the same parents that have required more chilling than that