How to Grow A
Giant Pumpkin
(How To Grow A Giant
Pumpkin from Don Langevin, author of the book How-to-Grow World Class
Giant Pumpkins)
If you ask 10 competitive pumpkin growers how to grow a giant pumpkin,
you're likely to get 10 different answers. It seems everyone has his
or her own way of coaxing the most weight out of these giants. But there
is a thread of consistency that runs throughout all the instructions,
and adhering to three basic tenets will get you well on the way to a
world record. Above all else, you need good seed, good soil and good
luck.
Good seed: If you want to grow a world-record pumpkin, you can forget
about every variety of pumpkin out there except Howard Dill's patented
Atlantic Giant. Since 1979, no other pumpkin variety has been a world
champion.
Good soil: Pumpkins are large consumers of all the major plant nutrients (nitrogen, phosphorus and potassium), as well as
many minor nutrients like calcium and magnesium and other trace elements. The key for big growth is soil well amended
with organic matter. In the fall or early spring, add two to five yards per plant of compost and rotted manures.
Cow and horse manures are best. Use chicken manure sparingly and only in the fall. Cover crops of winter rye, plowed
down in the spring, are fabulous. The soil pH should be between 6.5 and 6.8.
Good luck: If you can grow a good vegetable garden, you have the skill to grow a world-record pumpkin.
I've seen newcomers grow 500-pound pumpkins their first year with good seed, some rudimentary help from an experienced
grower and a lot of luck. With the right preparation and strategy now and in the spring (see the text on page 40 for
tips on planning your assault on the world record), next year you might just be a contender for the world championship!
- PREPARE THE SOIL. Start with a pH test in fall and adjust
your pH to between 6.5 and 6.8 by adding sulfur to lower the pH or
lime to raise it. Apply three to five yards of composted manure per
30-foot-diameter circle where you expect to plant next spring. Plant
a cover crop of winter rye in fall to be turned under in early spring,
broadcasting one to two pounds per 1,000-square-foot area.
- SOW SEEDS. Start seed indoors in six-inch peat pots about
four weeks before your last spring frost date. Plant the seed with
the pointed end of the seed facing down. Keep the soil temperature
at 85 to 90 degrees F. Most seeds will emerge within five days.
- TRANSPLANT SEEDLINGS. Transplant seedlings into the garden
once the first true leaves appear or when roots begin to grow through
the peat pot (usually seven to 10 days after germination). Handle
with care because pumpkins are easily set back during transplanting.
- PROTECT SEEDLINGS. Place a "mini-greenhouse" over the seedlings
for six weeks to shield plants from wind and frost. These mini-greenhouses
can be as simple as two storm windows nailed together to form a teepee
or as elaborate as a four- by four-foot wooden structure made from
1x2 lumber nailed together with 6-mil clear plastic stapled to cover
the frame. Once seedlings outgrow the mini-greenhouse, use a temporary
fence to screen wind. I use "conservation" fence, which is bought
with wood end stakes attached and is commonly used at new construction
sites. A 100-foot roll cut into three pieces is enough for three 11-foot-diameter
areas.
- POLLINATE FLOWERS. Eight to 10 weeks after seed starting,
the first female flowers will appear. They're easy to distinguish
because they have a small pumpkin at their base. If you want to get
a jump on your rival, you'll need to hand-pollinate the flowers. In
the early morning, locate a freshly opened male flower. Pick it and
remove the outer flower petals, exposing the stamen and fresh pollen.
Locate a newly opened female flower and gently swab the stigma (internal
parts) of the female flower with the pollen-laden stamen.
Getting a pumpkin set as early as possible, preferably before July 10, is key. The earlier you set a pumpkin, the longer it has to grow until harvest. Since these monsters can gain 25 pounds a day, losing 10 days in the early part of the season could put you well down the list at your local pumpkin weigh-off.
- REPOSITION SET PUMPKINS. Once a pumpkin has set, its position
on the vine becomes extremely important. Most often the stem grows
at a very acute angle to the vine. However, for optimal long-term
growth, the best position is to have the stem perpendicular to the
vine. If yours is not at right angles to the vine naturally, coax
it gradually, over about a week's time, until it is in that position.
Be careful, because at this early stage pumpkins may still abort or
you may injure the fragile stem.
- SELECT THE MOST PROMISING PUMPKIN. If one plant has three
strong vines, you could have as many as seven or eight pumpkins set
and growing by July 20. Now you must choose the best pumpkin and remove
most of the rest. Measure each pumpkin's circumference at the widest
point weekly or daily with a cloth measuring tape. Choose the one
that's growing fastest. Also, keep an eye out for the optimum shape.
Young pumpkins that are round and especially tall grow the largest.
- PRUNE VINES. Begin pruning vines early in the season to discourage
random growth and an out-of-control patch. Prune each main vine when
it has reached 10 to 12 feet beyond a set fruit. If you have a pumpkin
on a vine that is 10 feet from the main root, cut the end of that
vine once it is 20 to 24 feet long. Let side shoots off the main vines
get no longer than eight feet before cutting off tips. Train side
shoots so they are perpendicular to the main vine to accommodate access
to the vines and pumpkins. Bury the ends of cut vines to reduce water
loss.
- FERTILIZE. During the growing season, most fertility needs
of pumpkins can be met by applying water-soluble plant foods once
or twice a week over the entire plant area. Give seedlings a fertilizer
that stresses phosphorus, such as 15-30-15. Shift to a more balanced
formula, such as 20-20-20, once fruits are set.
By late July, use a formula that stresses potassium, such as 15-11-29. I apply water-soluble fertilizer at the rate of one to two pounds per week per plant from fruit set until the end of the growing season. Some competitive growers will err on the side of overfertilization. But too much fertilizer can hurt more than help. If the pumpkins start growing too fast, they will literally tear themselves from the vine and explode. A very fine grower in New England told me, "Slow and easy wins the race." Remember this whenever you feel the urge to overfertilize.
- KEEP TRACK. Measure your pumpkins at least weekly. Gains
in circumference can average four to six inches in a 24 hour period.
Measure the circumference of your pumpkins first parallel to the ground
around the entire pumpkin, from blossom end to stem. Next, measure
over the top in both directions: from ground to ground along the axis
from stem to blossom end, then perpendicular to the stem-blossom-end
axis. Add these three measurements together, then multiply by 1.9
to give an estimate of the pumpkin's weight.
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