Giant pumpkins are extra thick, dense, and can weigh anywhere from 150 pounds to over a ton. Once fully grown, these lumpy pale pumpkins catch the eye, for obvious reasons. Growing one seems like an impossible undertaking since they weigh as much as a car. Yet all you need is one small seed with all the right conditions to grow a giant pumpkin.
To Grow Giant Pumpkins you must:
- Choose a pumpkin variety that can grow large.
- Plant in a sunny location early in the season so the pumpkin has time to grow.
- Keep the plant watered.
- Fertilize as needed.
- Remove all pumpkins that form except the one that you want to grow to giant size.
If you follow these steps, your pumpkin might not reach the gargantuan levels of the behemoth that set the world record in 2016 weighing in at 2624.6 pounds, but you will easily reach weights more than 100 pounds. Keep reading for more details on how to get your pumpkin as large as possible!
Choosing the Right Breed
It all comes down to selective breeding and pumpkin genetics. Over 30 years ago, pumpkin grower Howard Dill played around with different hybrids and came up with the popular “Dills Atlantic Giant”. It comes as no surprise that every single world champion has used these seeds.
There are other pumpkin seeds that you can use if you prefer growing a different variety.
Pumpkin Big Moose
This fruit can grow from 50 pounds all the way to 125 pounds, which is impressive enough if you want to attract big crowds. It features a medium red-orange color with a nearly round shape. It takes about 110 days for the pumpkins to read maturation.
Pumpkin Dill’s Atlantic Giant
These seeds need no introduction because every pumpkin enthusiast knows about their potential to reach enormous levels. Dill’s Atlantic Giant requires plenty of space to grow and requires at least 125 days for full maturation.
Pumpkin Polar Bear F1
These pumpkins feature an odd color that resembles the thick white fur on a polar bear. Their long vines produce average sized pumpkins of up to 30 to 65 pounds, which looks impressive. It takes around 100 days to reach full maturation.
Interested in pumpkin varieties? Make sure to check out our post about the 73 types of pumpkins - from the smallest to the largest.
What Kind of Growth Zones is Ideal for Giant Pumpkins?
The ideal hardiness zones for pumpkins are 3 through 9. For maximum growth, make sure to plant them in an area protected from dry, hot winds. In the case of 8 to 9, farmers will need to provide additional protection to the pumpkins from freeze and frost in fall and spring. You may also want to check out these posts -
Weather Conditions for Giant Pumpkins
Pumpkins need plenty of sun to grow. Try to find the sunniest place in your garden.
Pumpkin vines die and injure fast when exposed to freezing temperatures, allowing rot causing bacteria and fungi to attack the fruit. The University of Illinois Extension notes that leaving pumpkins to in freezing temperatures will cause up to 90 percent fruit loss. The best time to plant giant pumpkins is to wait at least two weeks after the last frost has passed, or when the soil temperature is at least 15 °C.
Keep the pumpkins between 15°C to 38°C to harden and germinate them before transplant. Careful not to plant them too early because it will expose them to cold that could inure or rot the seedlings. The University of Minnesota Extension recommends transplanting only when the soil is at least 18°C.
If the temperature unexpectedly plummets during spring or fall, shelter the pumpkins with newspaper mulch or black plastic. Use row covers that can hold enough heat to hold off the frost until your pumpkins reach harvest.
Best Soil for Giant Pumpkins
Giant pumpkins are always thirsty for lots of water but don’t plant them in dense or wet soil. Make sure the soil is drained well. You don’t need tractors or any kind of machinery to dig down very far, digging up by hand will do just fine. Ready the soil in early spring, once the ground is sufficiently warm.
Fertilize the soil with at least four inches of rotting manure, cow manure. This is to create a soil with a pH value slightly near 6 or nearly 7.
If you live in zones 8 to 9 and there is danger of frost, you can start growing pumpkins two weeks before transplanting. Plant one seed per four-inch peat pot filled with peat moss. Make sure the pots are fully watered, do not let them dry out.
Choosing Fertilizers – which and how much
When pumpkins are still growing their leaves, they will need access to fertilizer that is high in nitrogen. Once they start growing their fruits, the fertilizer should have more phosphorous and potassium, both these nutrients encourage fruit growth. If you buy fertilizer from garden stores and don’t grow your own, start out with a high number such as 10-5-5, the switch to 5-10-5, and so on.
These numbers represent the percentages of the three main nutrients, nitrogen, phosphorous, and potassium. The first number is for nitrogen, the second and third are for phosphorous and potassium. Higher numbers represent a greater concentration of the nutrient.
Pumpkins have two flowers: male and female, these appear in July. The male flowers grow first, followed by females. To ensure your pumpkins grow up to big and plump, you have to select a big vine, so hunt for one before the pumpkin. Once you find a strong and well-established vine with a female flower that is about to open, cover it with plastic baggies to keep the insects out. The females can be easily identified because they have a baby pumpkin at their base.
Wait until the next morning to pick a fresh male bloom, remove its outer petals, and rub the pollen-filled stamen around the center of the newly bloomed female flower.
Read more: What do pumpkin flowers look like?
Isolating the Giant Pumpkin
Once a pumpkin has reached the size of a basketball, it is time to isolate it from other pumpkins and flowers on the vine. This is to ensure the plant feed only the giant pumpkin. If done right, the pumpkin will grow very fast and reach 60 pounds in size at peak growth. In the meanwhile, keep feeding and watering until then.
How Much Water is Needed?
Giant pumpkins are always thirsty for water. Make sure to spread around 3 to 5 inches of mulch, for example, weed-free straw and shredded leaves, covering the pumpkin vines. The mulch conserves water and minimizes the use of water.
Don’t use an excessive amount of mulch because they will absorb a lot of water and nutrients. A good rule of thumb is to keep a weed-free zone around the pumpkin plant.
Water Daily for Best Results
Irrigate the pumpkin plants every morning by using a garden hose pointing at the base. Avoid any spraying or splashing to prevent water from reaching the giant pumpkin’s vines and leaves. The water should be able to reach at least 6 inches of the soil.
Continue to water the pumpkin plants every day as is necessary to keep the soil moist. Irrigate the soil right after feeding your pumpkin plant. This is important because it carries the fertilizer to your plant’s roots.
It is important to avoid overhead sprinklers because they will accidentally splash to other areas of the plant such as the vine and leaves.
The bottom line is that this is a pumpkin variety, so if you're trying to grow one to its fullest size, be sure to read out detailed guide on how to grow pumpkins successfully.
How Long Does it Take to Grow a Giant Pumpkin?
Because you’re growing giant pumpkins, expect the maturation time to be anywhere from 125 to 150 days. This is to account for 60 days of plant growth and 80 days of fruit growth. The time for harvest ultimately depends on other conditions such as the climate, seed genetics, soil condition, temperature, pH value, and other factors.
Largest Pumpkin in US History
In 2018, the largest pumpkin in history weighs in at an enormous 2,528 pounds. It was grown by Steve Geddes of Boscaven who bagged the $6000 prize money.
Where to buy Giant Pumpkin Seeds?
There are many online stores to choose from, most noticeably Amazon, Burpee, and Harris Seeds. Amazon has the highest number of seed varieties to choose from while stores like Harris Seeds tend to be more selective.
Check out this link for an exhaustive list of 50 stores that offer pumpkin seeds.
Harris Seeds has over 3 different varieties for giant pumpkin growers, this includes the Pumpkin Polar Bear, Pumpkin Big Moose, and Dill’s Atlantic Seeds. It requires you to place a minimum order of $100 before shipping out, this makes them slightly more restricted than Amazon.
Burpee is a great online store for gardening enthusiasts, but at the time of this article’s writing, it only offers the Atlantic Giant for sale. The good thing is that you don’t need to place a minimum order for shipping.
Amazon doesn’t need an introduction because it is the biggest e-commerce retailer in the world. It has the largest selection of giant pumpkin seeds, including Dill’s Atlantic. The best part is the free shipping on select orders.
More pumpkins to consider
Why not try other varieties next to your giant pumpkin? Here are a few suggestions from our site -