WAXAHACHIE, Texas - Sometimes seeing is believing. When it comes to Joey Grmela's watermelons, even then, believing is tough.

"It's huge," he said. "It may grow to 200."

That's right. Grmela is growing a watermelon as big as a human. It's more than 48 inches wide. And it took three people just to lift it onto a scale.

"It's definitely a personal best," he said.

It clocked in at 158 pounds Tuesday. That's a little less than Grmela expected. But then again, it's still growing.

The whopping melon is affectionately nicknamed "Roberto," a nod to the man who helped build the greenhouse it currently sits in.

"I wanted to grow one that when people look at it, they say, 'My God!' That's what I'm doing," Grmela laughed.

Grmela is getting ready for an annual competition this weekend in Missouri, where growers from around the country bring watermelons that can top 300 pounds.

Grmela is one of the only Texans. "I'm sneaking up on 'em real fast," he said.

Ribbons and pictures have a spot of honor at his house. He won second place for a 162.5 pound beauty a few years back. A 154-pounder on display at the Ennis HEB stopped folks in their tracks.

"Half of 'em say, 'What are you putting those things on, steroids?' And I say, 'No, it's just giving them exactly what it wants," said Grmela.

And that includes collecting a massive amount of rainwater. "Right at 5,000 gallons for one melon," said Grmela.

He's strategically connected collection bins to rain gutters around his house and carport.

Early in the season, Grmela also chooses which melon he wants to focus on. Then, he picks all the others off the vine, so that all water and nutrients will help his chosen one grow.

"It's more of a perfect shape even when they're this long," said Grmela, on how he chooses.

He also replaces the soil annually, loosening it and mixing it with volcanic ash. "I have that soil sent to A&M, so I know exactly what I need to add," he said.

And he makes sure to only use seeds from other massive melons, which can cost $5 to $6 a pop.

A machinist by trade, Grmela has been growing the melons for 15 years. "It's a little hobby to keep me busy," he said.

His little hobby planted the seeds for a big dream. You see, Joey's not just growing melon, he's stretching himself too.

"I'm still learning, I'll be the first to admit. I'm still learning because there's guys growing them 300 pounds," said Grmela.

We don't know how big "Roberto" will get before it's competition weigh-in this weekend.

"[They grow] four to five pounds a day, they just, whew, they just keep blowing up," said Grmela. We know Grmela's dream will keep growing.

"My goal here is to just keep going until I get that world record," he said.

The final results should be by Saturday afternoon, and we'll let you know how Grmela does.