Rietema family with giant pumpkins

Marv Rietema of Sioux Center has grown large pumpkins to compete at the Clay County Fair in Spencer. They’re also enjoyed by his grandchildren, such as brothers Leo, 5, Luke, 10, and Perkins Rietema, 8.

SIOUX CENTER—When most people start a garden, it’s as a way to relax, but for Marv Rietema, it’s a place to challenge himself and push the limits of his green thumb.

For 30-some years, gardening has been one of the Sioux Center resident’s pastimes. It’s only been in the last 20 years that he’s been growing monstrously big pumpkins.

The 70-year-old said tending to gardens and plants keeps him in touch with his farming roots, and there’s an element of faith in gardening he likes, that locked inside the tiny seed is something that can potentially grow to more than 1,000 pounds.

Rietema likes the challenge and competitive aspects of it, too, since he takes his pumpkins to the Clay County Fair in Spencer.

“We’ve won the largest pumpkin there for the last five years,” Rietema said.

It’s his goal to grow a pumpkin larger than 1,000 pounds. The closest he’s come is with a pumpkin grown last year that weighed 840 pounds.

This year’s biggest pumpkin weighs about 700 pounds. He attributes the smaller size as the result of the same poor growing conditions all crop producers had this year.

When he started growing pumpkins competitively, he just wanted to see how he would do. Then it turned into how much he could improve the next year.

“I guess it’s like why people run marathons; they want to do better the next time,” Rietema said.

Early on, he learned that what he thought was big wasn’t quite so big after all. Rietema recalled taking his first big pumpkin, which weighed more than 200 pounds, to an event in Sioux Falls, SD.

“I loaded it up in the back of my pickup and took it down there. I pulled in there and just had to go, holy cow, am I getting smoked,” Rietema said.

There was another man who pulled in with a trailer hauling three pumpkins, each tipping the scales at more than 1,000 pounds. Rietema had the chance to talk with that man, who shared some tips with him.

Through the years, Rietema has been impressed with how willing these growers have been to share what they know with others.

Rietema is willing to share his lessons, too, though he warns that growing supersized pumpkins isn’t a leisurely endeavor.

“It’s a part-time summer job is what it is,” Rietema said.

He begins growing several seeds indoors around March. Starting them off indoors gains them some extra growing days and protection from any wild weather.

The right seeds must be used. Rietema grows a particular type of pumpkin called the Atlantic Giant. Depending on what the grower wants, the grower can get seeds from pumpkins bred with color, shape or size in mind.

When they’re brought outside, they need to be kept in a spot that’s sheltered from the wind but gets plenty of warm sunlight.

There also needs to be enough space for them from early on.

He recommended planning on having the pumpkin 10 feet away from the vine’s roots. If the pumpkin doesn’t have enough space, it can pull the vine out of the ground as it continues to grow.

The ones he grew this year came from seeds from a pumpkin that weighed 1,900 pounds.

“You can buy those seeds online. Some of them can get a little spendy. … You can pay up to $50 a seed for some of those,” Rietema said.

From early on, he has to make sure that only one pumpkin is growing on the vine so that all the nutrients are going only into one place. To further maximize the nutrients the pumpkin gets, he takes care to trim away all excess leaves and offshoots that appear.

“Otherwise, you can’t get a big one,” he said.

He grows them off pallets. Doing so early on allows them to be more easily lifted and moved when the time comes to cut them off the vine and haul them to the fair.

“You have to do that when they’re small because on a good, hot day, those things can gain 30 pounds a day,” he said.

To sustain that kind of growth takes a lot of water, as much as 30 gallons per pumpkin a day.

“I remember two years ago, I had the city call me one day wondering if I had broken a line somewhere,” Rietema said. “I said, no, I’m just trying to water four big pumpkins.”

To make sure they get enough water, he uses soaker hoses.

“You can’t water them from above; you have to water them from below because otherwise you’ll get a lot of fungus and diseases from being too damp,” Rietema said.

It also takes rich soil. He brings in compost from a cattle confinement.

“They’re heavy feeders. They need a lot of fertilizer,” Rietema said, adding that while they don’t need much nitrogen, they do need a lot of potassium.

Special care for the pumpkin’s skin is needed so that it stays pliable. If not, there is a risk that it will split or crack when it starts to get big.

There are different ways people go about that, such as putting up some shade for it or covering it with a cloth. Feeding the pumpkin extra calcium can help, and he’s heard of people rubbing lotion onto the pumpkin to keep it supple.

As he’s seen from these competitions, a lot of these massive pumpkins become distorted and bulbous when they get too big. But Rietema has found out that by gradually turning the pumpkin and its pallet up, he can better preserve its shape.

That must be done slowly and carefully; the stem is brittle and going too fast can mean prematurely severing it from the vine.

“I’ve snapped off many a nice pumpkin,” Rietema said. “I’ve finally learned that you got to be patient.”

As he can tell you, “These things are terribly touchy. It’s not just planting it and leaving it. It’s a constant thing. … They are a time consumer.”

That’s why he’s cut back how many he raises. At first, he’d try to raise about four or five pumpkins, but he’s cut that back to two or three.

When the pumpkins are done at the fair, he brings them out to the front of his driveway at his home on Ninth Street Southwest by the railroad tracks south of Tower Fields. For years, this has been a great spot for his family to take pictures, becoming an annual tradition.

Eventually, the pumpkins do have to go though, and when that time comes, the pumpkins become hog food for a friend. Rietema does keep the seeds for friends and others who’ve expressed interest in them.

Rietema himself doesn’t use those seeds, preferring to try out a new batch.

In addition to pumpkins, with the help of Owen Sandbulte he’s raised a large hog named Brutus. He’s also worked on growing tall corn for fair competitions.

“I have a better chance of getting that boar to be a state record than I do the pumpkins,” Rietema said. “Those guys must have some secret out there I’m not aware of, but I’m going to keep looking. I enjoy this. It’s fun.”