Sun, 17 Feb 2013 09:51:09 PST
OK, Ina. Well, I understand. I must explain that there was a particular
reason behind that question. I am beginning to doubt whether the emphasis
given to chilling in order to achieve good germination from winter-growing
bulbs (especially South Africans) is fully justified. I have acepted it
fully for years. In the past two my confidence in it has fallen. Let me

Two years ago I got an order of South African bulb seed from a reliable
source (Silverhill). I sowed in the way I have done for many years. Of all
the species sown only two (both Watsonia) germinated. I reported the results
here over a year ago. There were chilly nights and the nighttime temperature
profile matched pretty well what those species would have exprienced in
South Africa (Cape Province). Disappointed, I let all the seed trays dry out
in April, exposing them to sun over the summer for much of each day. In
effect, I forgot all about them. It was a hot summer. I did not bother to
water them in September or October. Light rain came in November but
temperatures were still not cool (minima over 50F (10C) for much the month).
Imagine my surprise when germination from all of the previously ungerminated
trays sprang to life in a matter of a few weeks. So, disappointed by the
previous year's results, I decided to simply let nature take care of it all.
More rain came in December and there was now very effective germination and
excellent growth without any action by myself. Only then did cold weather
come. The growth of seedlings of several species of each of Geissorhiza,
Sparaxis, Lachenalia, Gladiolus, Ixia, Watsonia and Ornothogalum continued
and still does, although by now I am tending the trays again!

The moral of the story is that chill temperatures in fall (autumn) appeared
to have no effect in the two years. It seems that whatever light chill was
there in November 2012 was sufficient. What was important was the
aestivation process, requiring seeds from the southern hemisphere to get
into synch with this part of the world. Previously, I had decried this
requirement. I had never seen it was needed for seeds of other southern
hemisphere seeds. All I have to offer by way of explanation is that the
seeds that did not germinate the first year were truly fresh, gathered in
say December 2010 or January 2011. Instead of receiving cool nights and
moisture as they would in South Africa in May 2011, they were subjected to
high temperatures but no moisture in San Diego until October 2011 when I
first watered them. Apart from the Watsonias they did not sprout. They
appear to have gone fully dormant for a full year, until Noember 2012.

Seeds from related species that have grown from my own stock always
germinate quickly and generally well before the temperature drops by much in
October and November. Lachenalias, a bit weedy alas, even spring up in
September without encouragement.

Comment anyone?


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