How to Grow a Giant Pumpkin — Green Adrenaline

If you are new to growing giant pumpkins and want a basic guide on how to get started, read the information below. I have articles that go into more detail on many other aspects of growing giant pumpkins, but this is a good starting point! If you are a more advanced grower, be aware that some of these methods and dates will not necessarily be applicable for a world record pumpkin, so adjust accordingly.

Pick your patch

Pumpkin plants take up a lot of space, so make sure you have at least 400 square feet to use. An ideal space would be 900 square feet (30 feet x 30 feet).
Make sure it is exposed to as much sunlight as possible.
Be aware that critters like deer and groundhogs will eat and destroy your pumpkin plant, so you may need to fence-in your patch!

Starting your seed

Plant your seed indoors around the last week of April (earlier if you live somewhere warmer than Maine!).
Before placing it in the dirt, file down the edges of the seed (EXCEPT for the pointed end where the new roots emerge) to help moisture penetrate better. File it down just until you see a color change.
Fill a 4-inch pot with soil and place the seed pointed end down about ½ inch below the surface of the soil. Water it and keep the soil moist, but not wet. If the soil is too wet, the seed will rot. The seed likes a temperature of 85-90 degrees when germinating. Keep your pot in a warm place (near the wood stove, on a germination mat, on top of the refrigerator, near a heater, etc.).
Once the seedling emerges, place it under a fluorescent light or by the window. If you use a fluorescent light, keep it just a few inches above the seedling to prevent it from getting “leggy”.
If the plant has a tough time shedding the seed coat, you may GENTLY peel off the seed capsule by hand.
Need a seed? Try Wallace’s Whoppers, or join your local pumpkin growers organization!

Move your seed outside

You want to get your seedling outside as soon as possible since the roots can quickly take over the pot and become root-bound.
Once there is no longer a threat of frost, you may transplant your seedling outside. If possible, place some compost in your planting area and mix it in with the soil. These plants are heavy feeders, and they need a lot of nitrogen (which easily leeches out of the soil in the spring) to grow the greenery.
The main vine will grow in the opposite direction of the first true leaf (the one in the middle) so remember this when transplanting.
Keep row cover or clear plastic over your plant, especially on cooler days. The plants will grow much faster if it is 80-90 degrees. If you use a greenhouse or clear plastic, you may need to vent it on warmer days.

Bug Control

Bugs are probably going to be your biggest problem in the pumpkin patch, particularly cucumber beetles and squash bugs. They can get out of control quickly.
Most top growers use pesticides to easily get rid of these pests, but even organic pesticides risk killing beneficial insects and bees.
I plant several blue hubbard squash plants on the outskirts of my patch to help with pest control. The blue hubbard squash is a trap crop, meaning the bugs like the taste of this better than the pumpkin. What I do in my patch is pull all the flowers off the blue hubbard squash plant (so it doesn’t attract the bees), and then I spray it with Neem Oil to help kill the cucumber beetles. It’s not a perfect system, and I often have to go out most morning to manually squish the cucumber beetles so they don’t get out of control.

“Training” your plant

Pumpkin vines grow very aggressively – up to a foot a day! If you don't prune and train your vines, it will turn into a jumbled mess. It’s okay if you decide to just let it do its thing, but if you’re looking for a record pumpkin, you really need to prune your vines.
The primary vine is the main vine of the plant. Secondary vines grow off that, and tertiary vines will grow off the secondary vines. In general, more vines equal more water and nutrient uptake for the plant, but sometimes too much is a bad thing. You want to limit how long these vines get. Remember, you are trying to grow a pumpkin, not a salad!
As the vines grow, cut off the tips of the secondary vines with pruning snips after they get to be about 15 feet long. Cut off ALL tertiary vines since these vines use up energy needed to grow your pumpkin. This diagram is an example of how I prune my vines. I do allow several tertiary vines to grow on the secondary vines just before the pumpkin. This is because the area of plant BEFORE the pumpkin is generally what feeds the fruit, and the vine after the pumpkin is not as important. I let the main vine grow the entire season because it sends growth hormones back to the pumpkin to tell it to continue growing.

Bury Your Vines

If you really want a giant pumpkin, burying vines is a very crucial, yet time consuming step.
At the base of each leaf, a root forms under the vine to allow the plant to take in more water and nutrients. If you bury the vine with dirt, it will form a second root on the top of the vine where you covered it.
As the vine grows, dig a trench in front of it to guide it and make burying vines easier. If you want an even better shot at getting a giant pumpkin, sprinkle some mycorrhizae into the trench when you bury the vine. Mycorrhizae is a fungus that forms a symbiotic relationship with the roots, allowing it to take in even more water. You can buy it in granular form.

Pollination

Around the first week of July, your pumpkin should be ready for pollination! If you have bees in your garden they will probably do the pollinating for you, but you can also do it yourself.
You will notice two types of flowers on your pumpkin plant: males and females. The males are characterized by long stems, and there are lots of them. The female flowers are fewer in number, and they have a baby pumpkin at their base.
Check your plant every morning around pollination time. When you see that the female flower has opened up, take a few male flowers, peel the petals off, and “paint” the pollen inside the female.
If you want to control the genetics of your plant, you should cover the female flower with a paper cup, or tie it with a zip tie BEFORE it opens up. This will prevent bees from cross-contaminating it. After pollinating with your chosen male flowers, cover it back up.
If you want to grow a record pumpkin, you only want one pumpkin per plant so all the plant’s resources go towards that one pumpkin. If this is your first time growing, you may want to have several pumpkins growing in case you lose one. Some people choose to let every pumpkin grow. Others will pick all the pumpkins off except for the one they deem to be “the one”.
For more details on pollinating, read my article, “How to Pollinate a Giant Pumpkin”.

“Painting” the pollen from the male onto the female.

Watch her grow!

Over the next few days, the petals on the female flower will wilt and fall off. If your pollination was a success, your pumpkin will start growing!
While the pumpkin is still small, place something underneath it to prevent it from rotting or getting eaten by insects/rodents from underneath. Mill fabric is a good base if you can obtain it. Other options are sand (since it drains well) or hard foam insulation.
Try to orient your pumpkin perpendicular to the main vine to prevent it from growing into the vine as it gets bigger. Do this in the heat of the day when the stem is more supple. If you move the pumpkin too much the stem might snap, so go slowly and do it over the course of a few days!
Place a white sheet over your pumpkin during the day to protect the skin from cracking in the sun. I got mine at a garage sale.
If you don’t get a lot of rain, be sure to water your pumpkin. Depending on your soil, you may need up to 150 gallons of water per plant per day!
Now watch your pumpkin take off. Your neighbors and friends will love it!

Want more information?

If you’d like to go the next step in regards to amending your soil, read my article, “No One Ever Fertilized an Old Growth Forest - My Organic Approach” that explains some of my favorite products in more detail.
If you’d like to go the next level from there, read my 2018 Growing Season Recap which outlines some new things I changed in my patch.
How to Lift a Giant Pumpkin - Dale and I use a tripod system to lift our pumpkin, and this explains it in more detail.
How to Make Compost Tea - Compost Tea is a great way to keep the beneficial microbes in your soil flourishing. It’s like a probiotic for your garden! This is how I make it at home on the cheap.
Maine Pumpkin Growers Organization - This site will give you more detailed information on how to grow a giant pumpkin. Many growers submit diary entries throughout the year which is helpful to see what others are doing during the growing season. You can also join for $20 a year to get access to premium seeds and bi-annual newsletters.