Each autumn, farmers across the country load their largest pumpkins into the back of pickup trucks and drive them into town for weighing. Some of the most enormous vegetables top out at more than 2,000 pounds, or one ton, and earn the growers thousands of dollars in prize money.

But have you ever wondered how a pumpkin can grow so big? Especially when most pumpkins that are used to make jack-o-lanterns weigh 7 to 10 pounds?

“You have to start with the right seed,” said Bob Westerfield, a horticulturist at the University of Georgia. “A Chihuahua is never going to turn into a Great Dane, even if you are somehow able to breed the two [dogs].”

This means that you can’t begin your quest for pumpkin greatness with just any pumpkin seed. Westerfield recommends using varieties named Atlantic Giant or Big Max, though he said you’re unlikely to find them at local stores. However, with the help of a grown-up, they should be available to buy online.

Next you have to do a little math. Each seed packet will come with an estimate for how many days it takes to grow to maturity. This is important, because if you plant pumpkins too late in the year, they may not have enough warm weather and sunlight to grow to their full potential.

Once you’ve chosen a planting date, make sure your pumpkins have enough food. This is done by adding nutrients to the soil, such as bagged topsoil and compost, when the seeds go in the ground.

Westerfield also recommends giving each giant-pumpkin vine plenty of room to spread out.

“One pumpkin plant can stretch out for 15 to 20 feet, almost like an octopus,” he said.

If everything goes according to plan, your pumpkin plant will produce lots of yellow flowers. Westerfield said each plant will have male and female flowers. The female flowers, which have a slight bulge at the base, will eventually turn into fruit. This is why he recommends choosing one or two female flowers and snipping off the rest.

Each plant can support only so many pumpkins. If you want to grow a giant, then you need to make sure the pumpkin plant concentrates all its efforts on one or two big pumpkins instead of lots of little ones.

Then all you have to do is water once or twice a week, add a little fertilizer now and then, and wait!

Eventually, you can turn your giant pumpkin into a giant Halloween decoration or leave it out for birds and deer to eat. Fair warning though — giant pumpkins aren’t that good for baking.

“Most people do it for the competition,” Westerfield said. “It’s not going to be for making 45 pies.”

Bittel is a freelance journalist who often writes about animals. His children’s book, “How to Talk to a Tiger . . . and Other Animals,” was published in April.

To our commenters

A reminder from the KidsPost team: Our stories are geared to 7- to 13-year-olds. We welcome discussion from readers of all ages, but please follow our community rules and make comments appropriate for that age group.