Ginormous gourds

Giant pumpkins: 7 scientific reasons these gourds get so chonky

‘Tis the season.

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As fall rolls around, competitive pumpkin growers gear up to unleash their monstrous gourds upon a fawning fanbase.

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There are pumpkin-growing competitions all over the world. The biggest contest in the U.S. is the Safeway World Championship Pumpkin Weigh-Off, which happens every year in Half Moon Bay, California.

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Dubbed the Super Bowl of pumpkin weigh-offs, this year’s winner is a gourd that weighed 2,191 pounds. That’s about the same as a young bull.

The largest pumpkin on record, ever? It clocked in at a massive 2,624.6 pounds.

Belgian farmer Mathias Willemijns smashed all the gourd goals in 2016 at a European weigh-in.


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Ordinary pumpkins don’t get that massive, so how do these behemoths even exist?

There is a science to getting the optimal growing conditions — choosing the right soil and seeds matters, and how you harvest the final fruit.

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Here are seven vital factors for growing a gratuitously large gourd:

7. Room to grow

Pumpkins — especially giant ones — like to spread their roots far and wide.

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Between 300-900 square feet is the ideal plot size for growing a giant gourd.

In other words, it needs up to the same amount of space as does a studio apartment in New York City.

6. Genetics

Farmers should pick seeds of pumpkin varieties that are genetically predisposed to grow bigger than more modest veg.


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For example, big pumpkins need a lot of water to grow.

Plants that grow fruit with tougher cell walls can withstand higher volumes of water traveling through tissues — so picking a varietal with that trait can help.

5. Leaves

Pumpkin plants have long, sprawling vines with leaves that reach for the Sun.

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As with all plants, the leaves kickstart the process of photosynthesis — turning sunlight into sugars.

But a giant pumpkin doesn’t necessarily make more sugars than its smaller cousins.

4. Anatomy

In 2014, researchers published a report on giant pumpkins, finding that the plants have another trick for getting so large.

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Big gourds have more transport tissue overall, which equips them to pump nutrients faster into all the parts of the quickly-growing fruit.

3. Competition

Far before a pumpkin enters a weigh-off, it has to compete with other fruits growing on the same vine.

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Farmers will limit how much fruit grows on one vine by culling the crop.

Having just one or two pumpkins on a vine forces the plant to funnel all its resources into these few soon-to-be ginormous gourd(s).

2. Sunlight ... or lack thereof

While sunlight is essential for the plant’s leaves to make food, too much can do damage.


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When the pumpkin starts to gain weight, growers will shade the crop to avoid the Sun damaging its tough skin.

1. Handle with care!

Even the smallest crack can disqualify growers of giant pumpkins from a competition.


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Giant pumpkins that grow too fast or that grow irregularly can be prone to bursting.

Sometimes, farmers will put a thin layer of sand underneath their crop so that the fruit slides easier on the ground as it expands.

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