Re: big leaves, long stems...

Temperature differential between day and night temps greatly affects stem elongation. There was a good list discussion of this back around May-June of 1998. Here are two links to messages from that era that can get anyone started who might be interested in digging around on this subject.

http://www.hort.net/lists/pumpkins/may98/msg00505.html

http://www.hort.net/lists/pumpkins/jun98/msg00007.html
This topic is very interesting to me. My experience seems to run opposite of
these archived messages, however!

I live in a high desert. We routinely have temperature swings between day
and night of more than 30 degrees, sometimes 40 or more. It can be 90's in
the day and 50's at night (good for sleeping!). Or of course we can have
60's in the day and 20's at night...Only once in a while do we stay above
60 at night.

While my plants were in hoophouses the stems grew to 2.5 to 3 feet, the leaves
were enormous. Since coming out they have returned to "normal" (what I've
seen the past three years...) smaller leaves on 1 foot stems. Also, my "nodes"
are very close together. I have three pumpkins pollinated on the main of the 652
all within about 1.5 feet of each other. (Of course two or more of these will be
culled.) And I have extreme difficulty reaching even 10 feet on the main in time
to pollinate. If I had room in the hoophouses and could have left them up for
another week, I'd be there now, easily.

On the other hand, I visited Vince's patch last year while on a business trip.
The temperature swings there are minimal. And he had enormous leaves on
3 foot stems, and a lot of space between nodes. 19 feet on the main vine at this
time of year is something I can only dream of. This seems to run counter to
the archived messages...

The hoophouses had temperature swings, perhaps even more so... They get much
hotter during the day (100+ on a 70 degree day) but at night when the sun goes
down, they cool to near ambient temperate.

So what causes big leaves on long stems? Or small leaves on short stems?
I've seen them both on the same plants this year, before and after the plastic
comes down... If it's not temp swing, then I think it might be related to:

HUMIDITY (extremely high in the hoophouses, and extremely low after they came down)

Or the plant tries to adapt to WIND (non-existent in the hoophouses, gale-force in
my neighborhood after they came down)

Or, SUNLIGHT (muted in the hoophouses versus full strength with little atmospheric
haze here in the desert)...

I'm interested in your thoughts, Cliff

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