I first developed this method approximately nineteen years ago for growing squash and have been refining it ever since. It is intended to produce the largest vine possible (12'+) by the ideal fruit setting date of June 20 to July 10th (based on my growing season). The second benefit is to obtain 80 to 90% of the pumpkin's growth by August 20th. In my area cool nights often start occurring the last week in August and can slow the fruit's growth. You also want the pumpkin to mature soon enough to stay on the vine for at least a week after it stops growing to let it harden off to prevent premature spoilage.
Reference the following to compare your area with the growing season this method was developed for.
* Average frost free growing season: May 25 to September 15th
* Latest recorded frost since 1973: June 10th (not a killing frost)
* Earliest recorded frost since 1973: August 25th (not a killing frost)
* Latest recorded snowfall since 1973: May 9th (all time record)
* Earliest recorded snowfall since 1973: October 10th (all time record)
SOIL PREPARATION: (reference fig:1) Prepare your soil as you would for any other method of giant pumpkin growing, but do it as soon as the soil can be worked in the spring. Well-drained deep loam is the best. After you have prepared the soil make a large flat topped mound approximately 4' around and 3' high. Before you excavate the inside locate a large window, i.e.: one from an aluminum storm window, and use it to determine the size of the hole. The planting hole should be approximately 8" deep with internal and external walls slanted to prevent them from caving in. Then bury a soil heating cable about 4" under the bottom of the planting hole. If you do not have access to electricity you can still use this method and get good results. Place a flat rock or a piece of slate on top of the soil in the center of the hole, this will be used to deflect water you pour in and protect the root system. The outside walls of the mound should be covered with black plastic to increase the heating by the sun. Then place the window on top to start warming the soil and keep the inside watered even before planting to prevent the walls from drying out and caving in.
Planting: I plant my seeds on April 15 plus or minus a day or so. Two days before planting plug in the soil heating cable, (if available), to keep the ground warm day and night. Plant the seeds about 1" deep around the bottom edge of the hole near the outside walls. I would plant eight to ten seeds if you have them. To increase germination you can treat the seeds with a fungicide that is listed for seed treatment. After planting place the window directly on the soil.
Before Germination: Keep window flush against the top of the planting hole until the seeds start to crack the ground. Exception: if the temperature is going to be above 70 degrees place two sticks, approximately 1" thick, one under each side of the window. "Keep soil wet!!" Even in rainy weather the soil can dry out under the window. Every night, frost or not, throw some sort of cloth or blanket over the glass touching the ground on all sides. If it snows leave the blanket on day and night until the weather becomes sunny.
After Germination: Keep the two sticks under the glass at all times. They can do better on a cloudy day if the window is down flush, but if you forget it and the sun comes out the plants may be killed. As mentioned above, every night frost or not, throw some sort of cloth or blanket over the glass touching the ground on all sides. If it snows leave the blanket on day and night until the weather becomes sunny. If high winds are predicted weight the window down with a couple of bricks. Make sure the soil doesn't become too dry. As the plants grow raise the windows so the leaves don't touch the glass by adding two more sticks in the opposite direction each time. When the plants have become so big that the window is eight or more inches above the soil, remove them. Immediately erect a wall of glass or plastic around the hill for a wind break. Make it so you can place sticks across the top to support blankets if there is going to be a frost. When the plants begin to send runners over the top of the hole tie them down in two directions with twine looped around the vine large enough to allow for growth. Keep these on until the plant sends down roots from the vine. The wind break should be left in place until the plant is so big it makes it impractical. A wind break around the whole Pumpkin patch is recommended at all times for better results.
Thinning: As the plants crowd each other, begin thinning. When the plants have three to four leaves you should be down to four plants one on each side of the hole. When its time to put up the wind break you should be down to two. Finally when the plants have four foot vines thin to one. This is when you look at the plant you've just pulled out and wonder if you have just killed the next "World's Record Pumpkin". Even so you must thin to one plant to grow a really big one.
Pest Control: With this early planting may come pests you usually do not see on Pumpkins planted later. The two major problems are some sort of Root Maggot and the Strawberry Root Aphid. The soil should be kept treated with a liquid insecticide mixture that is listed for control of root maggot. This will work well on the aphid too. When you're thinning watch for the small white maggot or the blue green aphid on the roots to monitor your success or failure.
Conclusion: As with any new method you try in the garden it will take some experimenting and refining. If you grow more than one Pumpkin you may want to try this on only one the first year to see how it works for you. This method combined with Compost Feeding Your Pumpkin (See 1993 WPC Newsletter) works great. Good luck in growing a really big one!
Last Updated: Fri Sep 06 10:30:00PM CST 1996