While raising produce in Illinois, I raised pumpkins as a fall crop. They ranged from the miniature pumpkins that could fit in the palm of your hand, to 150 pounders.
Illinois is by far the largest producer of pumpkins for cooking purposes. Many a giant pumpkin has been raised in the state and many others.
There is an art to raising giant pumpkins just as much as there is science behind it.
The first thing you need to do is buy the right seed. Not all pumpkin seeds are created equal.
The Atlantic Giant seed, also known as Dill’s Atlantic Giant for the gentleman who bred it, is the world record holder at this time.
This seed has been producing record breaking pumpkins for years, with fruits over 1,500 pounds.
The next step is to prepare your soil for next year. It is important that your ground be in optimal condition because giant pumpkins pull a lot of nutrients out of the soil.
Planting winter rye in the area you’ll be growing your pumpkins and turning it over in the spring will help with nitrogen content in the soil.
The optimal pH level for giant pumpkins is between 6.5 and 6.8. You can use sulfur to lower pH and lime to raise it.
Testing your soil for pH and macro and micro-nutrient levels is a good idea in the fall preceding planting.
Pumpkins like rich soil that is high in organic content, so mixing in lawn clippings as well as wheat straw can benefit you.
While it isn’t usually necessary to start pumpkin and gourd seeds indoors, Atlantic Giant pumpkins have a much longer time until maturity than most pumpkins do, about 115 days.
Start your seeds indoors under grow lights about a month before your last spring frost date. I’ve included a link below to help you find out what that is in your area.
You can use peat pots or pellets to start your seedlings. Put the seed into the pots point down. The soil should be between 85 and 90 degrees Fahrenheit and seeds will start to germinate in 5 days or so.
Transplanting should be done when the roots start poking out of the pot, or when the first true leaves begin to appear.
Take care when transplanting. If the plants are stressed in the transplanting process, it can set you back in your grow schedule.
Planting your pumpkins in the evening hours and watering them directly after transplant is ideal. This will help limit the stress they endure.
Once transplanted, using a mini greenhouse to shield your transplants. You can build your own small greenhouses out of 2×2 furring strips and 6-mil plastic.
Build it to about a 4’x4′ dimension. Nail the wood together and staple the plastic to the wood. After your plants start to outgrow the greenhouse, use silt fence to protect them from wind and animals.
They can be bought at hardware stores in 100′ rolls which you can cut into three equal pieces to make a perimeter about 11′ in diameter.
After about 10 weeks from transplant, your pumpkins will begin to blossom. It is important to get pumpkins set as early as possible, because your pumpkin can gain up to 20 pounds a day at the end of the season.
So losing a few days at the beginning can be the deciding factor when weighing in your pumpkin at the competition. To do this, you’ll want to locate female buds.
They are easy to differentiate from the male buds, because they have a tiny pumpkin attached to them. In the early morning, find a newly opened male flower and remove the petals, exposing the stamen.
Gently rub the stamen on the stigma, the female flower’s reproductive parts. This will ensure that your pumpkins set and set early.
It is important to make sure your pumpkin’s stem is perpendicular to the vine. Since they don’t typically grow this way, you may well have to reposition the pumpkin in that manner.
This should be done gradually, over a week or so to prevent the fragile stem from breaking or the pumpkin from being aborted. A strong plant with 2 or 3 main vines can have 8 or so pumpkins by July 20th.
Measure the circumference of each pumpkin with cloth measuring tape once a day or so for about a week. Choose the one that is growing the fastest.
Also, pumpkins that are round and especially tall tend to be the fastest growers. You must eliminate most of the pumpkins on your plant.
One per main vine or less.
Pruning vines is a necessary function to growing giant pumpkins. Don’t let vines grow much more than ten feet past a fruit.
This means that if your fruit is 8 feet from the base of the vine, your vine length shouldn’t be allowed to grow longer than 18 feet.
Don’t let side shoots grow longer than 8 feet. At the longest allowed length, cut the tip off of the vine and bury it. It will prevent water loss and also allow it to take root at that spot, helping to support the vine.
Fertilizing the vine for the most part can be done with water soluble fertilizer once every week. In the beginning, you should use a fertilizer high in phosphorous.
After fruit are set, use a more balanced fertilizer, like 20-20-20. Starting in late July, use fertilizers that are higher in potassium. This should be done through the rest of the growing season.
Some growers will over-fertilize which can hurt more than help. It is possible for pumpkins to grow too fast, causing them to split and tear themselves from the vine.
Another way to increase size is to keep a large jar full of water at the stem of each pumpkin. Make a tiny hole in the stem, just big enough for a lamp wick to fit into.
Insert the wick into the stem and the other end into the jar. It is very important that you keep the jar full of water.
The wick can have a reverse effect if the jar gets too low, pulling water out of the vine. Putting a small canopy over the pumpkin itself will help keep the pumpkin from being damaged by the sun.
Putting landscape fabric under the fruit at an early age will help keep insects and worms from boring into your pumpkins.
Using these steps, you can produce enormous pumpkins. It is tedious and time consuming, but the massive fruits of your labor will make it all worth while.