Tropaeolum tuberosum
Eugene Zielinski (Sun, 22 May 2011 11:30:29 PDT)

Hello Andrew.
Sorry to be misleading, but I can't grow T. tuberosum here in Augusta, even
in a greenhouse (which I don't have.) The summer nights are simply too
hot. I couldn't even grow T. majus here, except possibly as a winter
annual in a greenhouse.
Very shortly after I sent my e mail, a name flashed through my mind: Ken
Aslet. I did some checking on the internet and it turns out that T.
tuberosum 'Ken Aslet' is a day neutral form of the species. The "normal"
T. tuberosum is a short day plant. If T. tuberosum is a winter grower in
the San Diego area, then it probably won't bloom because the days are
getting longer as the plant is maturing. If T. tuberosum grows over the
summer, however, it should have no problems setting buds as the days
shorten in the fall and winter. Of course, if you are growing 'Ken Aslet,'
my discussion is moot.
Hope this all makes sense, and thanks for continuing the discussion.

Eugene Zielinski
Augusta, GA

[Original Message]
From: AW <awilson@avonia.com>
To: Pacific Bulb Society <pbs@lists.ibiblio.org>
Date: 5/22/2011 1:11:37 PM
Subject: Re: [pbs] Tropaeolum tuberosum

Dear Eugene,

Thanks for making the suggestion. Let's consider it. T. tuberosum comes

from

Peru, which is pretty close to the equator and thus has daylengths that

vary

little from 12 hours all year. In San Diego, at 33 degrees from the

equator,

daylengths range from about 10 hours in midwinter to almost fourteen in
midsummer. On that basis alone it would seem the daylength being either

too

short or too long as an unlikely cause. However, one might say 'well,

maybe

it's the day length at the time leading up to when the plant found
temperature conditions were also right to grow and bloom'. I suspect, but

am

not certain, that could be any time here from April to September, the time
of warm temperatures outdoors, during which daylight hours range from over
12 through 14 and back to 12, not to quibble about which week of the month
when we're starting or ending. That would seem to say that daylight length
is not the answer. You might come back and narrow down the temperature
blooming time to limit you to midsummer and say that they really wanted a
shorter day at that time of year. Well, OK, but that is getting very

picky.

It could, however, be tested by growing the plant in a greenhouse that

gave

a longer growing period. There are surely many more people at similar
latitudes that grow the plant indoors. I note that Augusta, GA is at a
latitude pretty close to that of San Diego. Do you have a g'house or do

you

grow it outdoors there? Let me know. Thanks!

Andrew
San Diego

I wonder if T. tuberosum's refusal to bloom is due to daylength problems.
Perhaps San Diego's days are too long, or not long enough.

Eugene Zielinski
Augusta, GA
USA