Harvesting tubers

[McClements, Jim]

Kristl

I would think that vermiculite should probably work well. The trick is to
have the right amount of moisture. I've come to the conclusion that the
smaller the tuber, the more dampness needed.

Another thing that you will discover is the importance of considering what
makes it easiest to find the small tubers when you "unrefrigerate" them. One
trick is, after finding the ones that are obvious, add a bit of water, which
will usually float the remaining tubers to the top in the container that
you've dumped the bag contents into. Vermiculite might not work well here,
since I assume that it floats. However, it might be easier to find the small
ones in pure vermiculate, making the "floating" procedure unnecessary.

As for refrigeration time, if you plan to move them along on under lights,
there is an obvious advantage  to a short "artificial winter". Three months
is certainly adequate, and is what Craig has been doing. However, Tony Avent
told us a few months back that he has had success using only a ONE month
chilling cycle. I recently did an experiment with two batches of A.
sikokianum, trying 20 with 3 months and 20 with one month's refrigeration.
Both groups responded by breaking dormancy, but the group that had only one
month's cold took a month longer to appear, and by the time that both pots
had been carried along through the growth cycle they ended up pretty much on
the same schedule. Contrary to what Craig has reported, I could see no
difference in the size or apparent vigor of the two groups.

If you don't plan to try to "push" these plants through artificial seasons,
there's probably no harm in keeping them refrigerated for more than 3 months.
However, check them occasionally for excess dry or wet, and to see in any
have broken dormancy while still refrigerated. They do seem to have some sort
of an internal calendar, and I have occasionally found refrigerated tubers
fully sprouted!

Jim McClements