Re: New look on old problem
Hey Kevin,
I've thought a lot about how temperature variations may cause a
pumpkin to lose it and split. However, if the pumpkin is
colder than the plant I don't think that the temperature of the
incoming fluids through the stem will have much of an impact.
Keep in mind that even if the pumpkin is growing at 25 pounds a
day, the incoming fluid is entering only at the rate of a fast
drip. At this rate, it will be chilled fairly quickly by the
huge mass of the pumpkin and cause little overall temperature
variation.
All blossom end splits that I have seen were a result of a thin
wall section around the blossom end. As the pumpkin adds
poundage, the sides settle and the thin area around the blossom
is unable to take the forces and splits radially out from the
blossom. I believe most blossom end splits are structural
failures of this sort and are primarily a genetic problem.
I'm sure there are blossom end splits caused by other factors.
I just have never seen one. I always watch for a deeply
concave blossom end as this usually means it is thin and
subject to splitting.
As far as the effects of temperature variations go, I believe
that they can cause splits to the cavity and internal spliting
which results in sag lines. Sag lines in turn can progress
into fatal splits to the cavity.
Consider this, a pumpkin sits under a shade all day on a day
that averages 80 degrees. It slowly warms throughout the day
to about 75 degrees and the soil temperature also rises to
around 75. That night the air temperature drops to 50. The
top of the pumpkin exposed to the night sky will cool rapidly.
The bottom half of the pumpkin sitting on the warm earth will
cool slower.
For those of you who are familiar with the concept of black
body radiation, the night sky draws radiant heat from the earth
as if the sky were at -50 degrees farenheit. This is why car
windsheilds can frost up on nights that the air temperature
only drops to 37 or so.
If the pumpkin is exposed to the night sky, the top surface can
get colder than the ambiant air temperature! Since the growth
of pumpkins slows considerably at lower temperatures, you now
have a situation where the top half of the pumpkin is growing
slower than the bottom half - on the road to splitsville in my
opinion.
My solution is to cover the pumpkin at night with a heavy
blanket. This lowers the heat loss on the top side and keeps
the pumpkin at a more even temperture from top to bottom - so
it grows more evenly.
Now... aren't you sorry you got me started??
vince
--- Pumpkinpirate1@aol.com wrote:
> Hi all
> OK here is a subject no one likes to talk about BUT I wanted
> to share some
> ideas with you all..
> I was at a growers house a few weeks ago and the grower
> had a pumpkin
> growing faster then anything we had seen in southern CA in
> years. he had built
> Gregory Cabins over it and it was totally grown in the dark
> So far so good. well
> what sticks out in my mind was I was beginning to sweat as it
> was around 85
> degrees with bright sun the grower commented as he touched
> the pumpkin that is
> was Very cool. I felt it and in fact it was cold in my
> opinion.
> Two days later this pumpkin split and the heat question
> came up in my mind.
> If you cover your pumpkins to insulate them and the plant
> warms up faster
> then the Pumpkin as the warm juices fill the shoulders it may
> cause a temperature problem in the pumpkin.
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