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Key points.

GROWING GIANT PUMPKINS


                                          Basic Cultural Practices
                                             by Joel Holland

SOIL PREPARATION: 
Minimum space is approx. 300 sq. ft. per plant. Doubling this space or
even more would be an
advantage, and will generally result in a larger pumpkins. Prepare the
soil by cultivation. Rake out larger stones, clumps
of sod, etc. Incorporate into the soil an inch or more of organic matter
in the form of compost, aged manure, peat moss,
leaf mold, or rotted straw. Adjust pH to 6.0 - 7.0. Prior to planting,
broadcast a balanced organic or commercial granular
type fertilizer, and work into the soil. 

STARTING SEEDS: 
Start seeds in 4" peat pots about May 1 - 10, depending on local
conditions. The tendency is to start
too early, which generally works against the grower. The plants will
need warm soil and settled weather to grow well.
Seeds germinate best at 80 - 95 degrees F. Germination will be slow and
may fail at cool room temperature of 65 - 70
degrees F. A commercial propagation mat may be used, or a warm
micro-enviroment found. Some examples would be: 

Over a hot water tank, 
In the oven with just the light on, 
In a cooler chest with warm bottles of water inside, 
On a mantle near stove, etc. 

Excess heat is to be avoided and moistened pots must be covered to avoid
drying. Fill moistened peat pots with a good
light potting soil.. Seeds may be pre-sprouted between moist towels to
1/4" root protrusion and then planted one to each
4" pot, rooted side down and 1/2" soil over the rounded end.

TRANSPLANTING: 
After 2 - 5 days, transplant the potted plant to prepared growing beds.
Protect young seedlings with
properly ventilated cloches or mini-greenhouses. Water as necessary to
avoid heat stress or wilting. When well
established cloches my be removed. Wind protection my be needed until
plant is well anchored with vines on the ground.
Mound soil over vines at several leaf axils to stabilize plant and to
encourage secondary rooting from the vines. Water as
needed, adding balanced soluble fertilizer to water once per week.
Control weeds with mulching, shallow cultivation, and
hand weeding as necessary. Remember, shallow roots may extend 4 ft. or
more out from perimeter of the plant.

FRUIT SET:
 The plant should blossom and set fruit between July 1 and 20. Male
blossom will appear first. Males are on
long stems with a rod like structure inside the flower which is coated
with pollen. The first open male flowers will generally
be towards the center of the plant. Female flowers are on a short stem,
and have a small round yellow pumpkin behind the
flower. 'The first female flower to open will be out from the center of
the plant on one of the vigorously growing vines. In
the absence of bee activity or to get an earlier set, the grower my hand
pollinate a newly opened female blossom with
several of the fresh male flowers. Pick several newly opened male
flowers and tear away the yellow flower portion,
exposing the pollen bearing stamen . Leave part of the stem to use as a
handle and gently roll the pollen from the males
onto the stigma in the center of the newly opened female blossom.
Depending on temperature and weather, this is
generally done from early to mid morning. Males from the same plant as
the female to be pollinated, may be used, (self
pollinated). However-,: for best seed quality, it is best to use males
from a separate and not closely related plant, (cross
pollinated). The plant must be large enough to support a fast growing
pumpkin, therefore setting a fruit too early can have
a negative result. The plant should have a minimum of 100 - 150 leaves
before a pumpkin is set.

PRUNING: 
To avoid rampant crossing vine growth, it is advisable to trim and
prune. Generally 3 - 5 primary vines are
allowed to grow out from the center of the plant in different
directions. Side vines will develop on each of the primary
vines, alternately at each leaf.. These side vines are allowed to grow,
but are trained away from one another or pinched
back before they cross. These side vines would in turn produce their own
set of vines alternating at each leaf.. The third
set of vines (tertiary vines) are removed from each secondary vine when
they are small or in the bud stage. This results in
a more open plant with better air circulation, which can help prevent
disease problems. A pumpkin can be set on each of
these primary vine structures. After 2 - 3 weeks select down to the best
2 pumpkins.

STEAM STRESS: 
Stress or tightness can develop where the stem of the pumpkin attaches
to the vine. The vine must lift
off the ground as the pumpkin grows taller. The vine will be rooted to
the ground on the under side. These roots must be
severed several feet each way from the pumpkin. Also as the pumpkin
grows the shoulders of the fruit on the stem end my
contact the vine and create stress. This usually happens on the side
away from the center of the plant. The pumpkin may
be moved very slowly 1 inch per day until it is at a 90 degree angle to
the vine, ( both shoulders equal distance from the
vine on each side of the stem). Never move the pumpkin early in the
morning as the stem and vines are brittle when it is
cool. Adjustments should be made a little at a time in the afternoon,
starting when the pumpkin is approx. basketball size.


It is helpful to have the pumpkin growing on the outside of a curved
section of the vine.  In this way the pumpkin will have more room to
develop without pushing on it's vine.  The  vine can be manipulated at
the time of fruit set, so the female blossom is on the outside of a
curved section of the vine.  Stem stress symptoms can develop very
quickly with a fast growing pumpkin.  The vines near the pumpkin should
be checked frequently for tightness.  As the pumpkin grows taller,
several feet of vine will be supported by the stem of the pumpkin in
both directions.  It is helpful to support the weight of the vine with
blocks of Styrofoam or other material in order to take the stress of the
stem.

Shading:
When the pumpkin is small, it will be shaded by the leave of the plant.
When the pumpkin grow larger, shade should be provided. Shading reduces
the aging stress of direct sunlight on the tender skin of the fruit, and
allows the shell to expand and stay flexible longer.  Shading also
reduces the internal temperature of the pumpkin,  reducing the threat of
rotting or splitting.

Splitting or cracking:
Each year many large pumpkins crack or split while growing at a rapid
rate.  We walk a fine line.  The grower wants his pumpkin to grow as
fast as possible in order to reach a large size, and as a result may
step over the unmarked line ( Sustainable growth curve).  Some seed
stocks are more at risk than others, especially those with genetic
potential to produce pumpkins over 700 lbs.  Some factors which may help
to avoid splitting include:


*	Try to grow your pumpkin at an even moderate pace over the
entire season. 
*	Avoid large doses of fertilizer and water at critical phases of
the pumpkin growth cycle. 
*	High level of soil organic matter and an even concomitant
moisture level can help moderate and buffer against growth spurts and
stops. 

*	
 Multiple fruits on a risky cultivator, may act as shock absorbers,
spreading a surge in uptake over two or there pumpkins.  Minor cracks
can be managed by applying a fungicide and reducing water and fertilizer
to the plant.  Stem splits often appear much worse than they are.  The
stem is hollow and may split all the way through and tear into the flesh
of the pumpkin a small amount.  Sometimes this releases the stress
allowing the pumpkin to continue to develop.  Treat all wounds sites
with fungicide, allow for good air circulation, and keep the area dry.
Occasionally a stem split or a surface crack will continue to expand and
deepen until the seed cavity is breached.  Once the seed cavity is
exposed to the outside atmosphere, the pumpkin is no longer a viable
candidate for competition.  No effort should be taken in regards to
plugging or patching, as the pumpkin will rot from the inside out.


Duncan McAlpine
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