[NAFEX] freezing scions

Hal Love lovehd at comcast.net
Wed Jan 28 11:33:59 EST 2004


I think the important thing to keep in mind about storing anything in a
freezer and keeping it viable, is the defrost cycle. Most freezers now are
frost-free types, which mean they periodically warm up to melt the frost
buildup and then remove the moisture from the air. I have never stored
scions in the freezer, but I have stored pollen, and this freeze/thawing can
be the kiss of death.

I suspect the reason that total immersion in a block of ice works is due to
the heat sink effect of the ice, which prevents the scions from warming
during freeze/thaw cycles. Dehydration would also be prevented or reduced,
which may be as bad or worse for the scions as the repeated formation of ice
crystals in the tissues. I suspect you could wrap scions in such a way as to
prevent dehydration and then store them in a container with sufficient mass
to keep them at a constant temperature, and get the same or better survival
as the solid ice block method. For my pollen storage, I place the vials in
between "blue ice" cold packs, wrapped in duct tape, and have had no
problems so far.

Hal



> The first year I froze scions it worked beautifully the second year I did
it
> differently and it was a total failure.
> The first year I put the scions in a plastic bag then submerged it in a
> three gallon jug which I put in the freezer. I took them out in mid June
and
> grafted them and the takes were nearly the same as for scions that weren't
> frozen.
> The second year I tried to save space by putting them in bags and then in
> small, long trays filled with water. The water didn't cover all of the bag
> and so there were areas in the bag taht weren't protected by ice but
rather
> only by a thin layer of plastic (between it and the freezer air). Thus I
> believe the failure.
> Kevin Bradley





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