What Does It Take To Grow the Biggest Pumpkins in the World?

October is a month for giant gourds. For pumpkins, growers are testing the limits on just how giant these gourds can get. Growers everywhere spend their springs and summers prepping to grow a champion pumpkin.

Scientific studies have yet to explain the best ways to grow the giant pumpkins. However, to push a pumpkin's limits, growers must consider the seed's genetics, soil health, beneficial insects, fertilizer, and concoctions of beneficial bacteria. So, how might the next record be broken? What does it take to grow the biggest pumpkins in the world?

The first great big pumpkin competitions sprouted towards the late 19th century and the beginning of the 20th century after William Warnock grew a 406 pound "Mammoth" giant pumpkin.

Current weigh-in competitions began around the 1970s and '80s, where pumpkins started to explode in size. But the pumpkins didn't get this enormous on their own. Several decades of breeding for their bulbous potential inflated the fruit, from winning county fairs at 400 pounds to tipping the scales at over 1000 pounds.

To grow a giant pumpkin, competitors experiment with various methods to plump up their fruits. But a prize-winning pumpkin comes down to genetics, like any winning show dog or blue-ribbon cattle at the state fair. "We're only a few years away from 3000-pound pumpkin, so that can't happen without a lot of people working together," Wallace says.  

The heavy gourds all stem from a Cucurbit species called Cucurbita maxima and can be traced back to the Mammoth cultivar. More specifically, genetics from the phenotype called “Dill's Atlantic Giant,” cultivated by Nova Scotia farmer Howard William Dill, are found in show pumpkins today.

"One of the keys to growing a giant pumpkin is to use the variety of "Dill's Atlantic Giant." Because that one just has [the] genetics to grow really big pumpkins; over two or 300 pounders," says James Myers, a vegetable breeder at Oregon State University.

When growers could share their expertise on the internet, pumpkins grew even bigger, weighing closer to 3000 pounds.

"All of us growers strive to keep getting better every year. The only way this hobby has got to this point is that everybody has worked together. There was no hiding of secrets, it was all sharing of knowledge and seeds," says Wallace. "That genetic potential is all because we've all made these generic hybrid crosses over the years."

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In 2021, the world record was awarded to Stefano Cutrupi from Italy, with a pumpkin weighing in at 2708.8 pounds. And 2023’s winner, Travis Gienger, broke the giant pumpkin world record at the 50th World Championship Pumpkin Weigh-Off at 2,749 pounds.

"We're seeing the world record holding for a few years at a time, which means to me we're slowly creeping towards the top until we find that next silver bullet, the next thing that's going to push these [pumpkins] over the top," says Ron Wallace, a champion pumpkin grower and owner of Wow Wallace Organic Wonder products.

Ron Wallace was the first grower to cultivate a pumpkin over 1500 pounds in 2006 with a 1502-pound pumpkin. He broke records again in 2012 after exceeding the 2000 pound mark with a fruit weighing in at 2009 pounds.

Pumpkins got bigger because growers on forums and websites, dedicated to learning the best techniques, shared their giant pumpkin seeds, soil practices, growing tools and the best ways to anchor a pumpkin as it grows. In combination with all these methods, growers also grew seeds with the best genetics and crossed them with other pumpkins to try and produce a champion, says Wallace.

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Once a grower has the genetic potential for the next great pumpkin, they turn to new techniques like growing the fruit inside greenhouses, utilizing soil science, and fertilizer mixes. Fruit champions also keep a watchful eye and constantly tend to their pumpkin. Because of this, Matt DeBacco hasn't taken a vacation in years. His summers are dedicated to growing a whopper of a pumpkin, hoping to beat the next state record in Connecticut.

"In fact, the only vacations you'll see are the years I lost them [the pumpkin] early. Then I go out and have a vacation. I'm rarely gone for even more than 24 hours […] because you just try to stay on top of problems [with the pumpkin]," says DeBacco, a horticulturist at the University of Connecticut and giant pumpkin enthusiast who has been growing for over two decades.

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Some of the techniques that can be used for growing a pumpkin include greenhouse control, proper soil temperature and conditions, and watering.

Setting up a greenhouse to control environmental conditions for the pumpkin and cutting off all surrounding fruits to focus on only one pumpkin can be helpful for harvesting giant pumpkins.

Other giant pumpkin growers, like DeBacco, may also bury heating cables underneath the soil to help keep the soil around the pumpkin warm as they establish viable roots and continue to grow. Pumpkins won't tolerate cold soil and do best in soil temperatures between 70 to 90 degrees.

Another method for healthy pumpkins is adding borax for calcium in the soil, infusing their fruit's greenhouses with carbon dioxide to jump-start growth and using different soil concoctions infused with mycorrhizal fertilizer.

To further aid a giant pumpkin on its journey to glory, growers must water them daily, but not too much, or they may split. At their peak, giant pumpkins can grow up to 50 pounds daily, according to North Carolina State University.

Forums and conventions held by giant pumpkin organizations focus on teaching growers watering techniques and meeting with soil experts, says Wizzy (Gary Grande), the pumpkin wizard and president of the Great Pumpkin Commonwealth.

"So, there's a lot of science that goes into growing these giants over 2000 pounds and above for sure," says Wizzy.

But, while theoretically, the genetics look good and all the best pumpkin patch practices have been used, crosses between champion pumpkins might not work out, and the pumpkin might split, disqualifying the grower at competitions.

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Other factors, like a combination of faulty genetics and the environment, may affect growth even in the best circumstances. DeBacco's pumpkin this year in 2023 met an untimely end when he discovered a fatal split in its side.

He suspected fluctuating temperatures and too much water created the split, despite using seeds and pollen from previous gigantic state champions.

Both DeBacco and Wallace say that this growing season was affected by unusually wet weather. The Northeast had the wettest July on record this year, according to the Northeast Regional Climate Center.

"If you don't have good weather, it doesn't matter what you're using [to grow pumpkins], weather will dictate the end results," Wallace says.

Wallace explains that one average grower will use 100 to 150 gallons of water a day, but with even an extra inch of rain, the pumpkin could be drinking an additional 660 gallons of water.

Too much water can cause a split, and insufficient sun can affect growth overall. Pumpkins grow best in sunny conditions.

"If you're growing outside, Mother Nature has a lot to say about it too. She can ruin your day and in 30 minutes, your whole season in 30 minutes," says Wizzy. To win, "It's just a combination of the right seed, the right soil, the right techniques, good luck, and Mother Nature taking a break," says Wizzy.

But, overall, when growing pumpkins, Wallace says the biggest thing is to have fun.

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