Rotting Tubers

[Wills, Simon]

Jim,

>>I take it that after the sulfur dusting you allow the tuber to dry out for
>>several days before replanting? Do I also understand correctly that you
check
>>for offsets in 5-6 months or so?

My method is born of a mixture of idleness and lack of frost-free space.   A
few years back we had too many large pots of arisaemas to store in the shed
and they were unattractively heavy to lug through the house to the cellar for
the winter, so I decided to tip them out when they died back in October and
just store the tubers dry.   This gives a good opportunity to collect up
offsets for exchange and to inspect for rot.

If rot is found they get the cleaning up and sulfur dusting and are then left
dry in trays until late February/ early March (depending on the winter
temperature) when they are re-potted.   'Dry' is a relative term - the cellar
is below our 18th century house and the temperature stays between 5 and 10
deg. C all winter, but nothing like the low relative humidities you can get -
probably 70 - 90 %.

Most of the rotting problems seem to stem from too much water too early in
the season, before they get into full growth, and also too much water when
they are dying down for the winter.   The species grown are mostly from the
Himalayas and are used to monsoon rainfall from July to August.

>> How long would you wait before discarding the tuber, or would it depend on
>>whether it had disappeared or not?

Normally the tuber just disappears before the end of summer.   If there is
any sound material with a growing point on it the plant seems to have a good
go at producing an offset.

I would be interested to hear if the Chinese and Japanese species respond in
the same way, or whether the climatic conditions keep the plants growing
slowly through the winter - when dry storage would not be possible.

Simon Wills.