| SOIL
PREPARATION:
Minimum space is approx. 400 sq. ft. per pumpkin plant. Twice
that space or even more would be an advantage, and will generally
result in 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. Giant
pumpkin 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
microenvironment 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 a stove, etc. Excess
heat is to be avoided. Seeds may be pre-spouted 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 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 may be removed. Wind protection may 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
1st and 20th. Male blossoms 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 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 grow -er may 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 pollenbearing 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 " is generally done from earlv
to mid morning. Males from the same plant as the female to be
pollinated may be used (self-pollinated). However, for best 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. The 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. This third set of vines (tertiary vines) is 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.
STEM
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 form the pumpkin. Also as the pumpkin grows, the
shoulders of the fruit on the stem end may 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 stems 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 approximately
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 its vine. The
vine can be manipulated at the time of fruit set. Set the female
blossom 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.
When 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 stress off of the stem.
SHADING:
When the pumpkin is small, the leaves of the plant will shade
it. When the pumpkin grows 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 split or crack
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 pounds. Factors which may help to avoid splitting,
include:
- Try
to grow your pumpkin at an even moderate pace over the entire
season
- Try avoiding
large doses of fertilizer and water at critical phases of
the pumpkin growth cycle.
- Try having
a high level of organic matter and an even concomitant moisture
level to help moderate and buffer against growth spurts and
stops.
Multiple
fruits on a risky cultivar may act as shock absorbers, spreading
a surge in uptake over two or three pumpkins. Applying a fungicide
and reducing water and fertilizer to the plant can manage minor
cracks. 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 develop. Treat all wound sites
with fungicide, allow for good 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.
PESTS
AND DISEASE: Problems vary widely from region to region.
In the Northwest, giant pumpkin plants are relatively free of
pest and disease problems. Sometimes black aphids appear on the
undersides of the leaves later in the season. Aphids can spread
the mosaic virus, but this hasn't been a major problem for Northwest
growers. It is best to contact an experienced local grower for
specific problems in a given area. Information may also be available
trom County Agricultural Agents and garden centers in regards
to insect or disease problems affecting pumpkins or squash in
region. Where vine borers and cucumber beetles are present. plants
may need preventative action before pests are active.
HOLLAND'S LAND O'GIANTS
Joel and Mari Lou Holland, P.O. Box 969, Summer. WA 98390 |