On August 1, 13-year-old Harold Harris pollinated some giant pumpkin seeds his grandparents had gifted him, and that he had planted earlier in the season. At the time, he wasn’t sure how large they would grow.
Now, Harold finds himself with two giant pumpkins. The smaller one is 340 pounds, as of a weigh-in this weekend. The larger pumpkin, weighed Thursday, is 535 pounds.
Harold has been tracking his pumpkin’s progress by taking daily measurements and plotting growth curves.
“I add up all of the [circumferences], and then I convert that to inches, and then I got a table in the book that shows me what that is equal to for the weight,” Harold explained during a recent interview in his garden. “It’s usually within five per cent [accuracy].”
The pumpkins were grown in a patch of soil at his home in Edgartown, and required careful monitoring, especially in periods of rapid growth.
Harold now estimates the pumpkins’ growth rate to be between four to six pounds per day, but at its peak they were growing about 27 pounds a day.
“I gave it maybe 100 gallons of water per day in the middle of summer, and now it’s maybe 50 gallons,” Harold said. “And every other day I give it some fertilizer in a soil drench.”
He uses drip irrigation and fertilizes the pumpkins with seaweed weekly.
“Once a week I do a soil drench, and sometimes I do a foliar spray,” he explained. “I also soak towels and stuff in calcium and put them on the pumpkin. That’s supposed to help thicken the walls.”

Harold has loved gardening for years, even before his interest in giant pumpkins took hold, said his parents Marty Harris and Emily Reddington.
“He grows figs, he prunes trees, he goes and takes all the adult classes at [Polly Hill Arboretum],” his father said. “He brings down their average student age by a lot.”
Not one to rest on his laurels, Harold is already strategizing for next year, which he think could be even more impressive as this year might be a “skip-year” pumpkin.
“If you get a seed from, say, a 2,000-pound pumpkin, it might only produce a four or five-hundred pound pumpkin,” Harold said. “But the year after that, you might get back up to 2,000 [pounds] using the seeds from the 500-pound pumpkin.”
While some giant pumpkin growers might be interested in the awards or notoriety associated with the discipline, Harold is uninterested, at least for now.
“They’ve got some [competitions], but I think I’m probably just going to wait and carve it,” Harold said.
In October, Harold plans to harvest the pumpkins and put them in the garage for safekeeping. Then, he hopes to carve something special for Halloween.
“I’m going to try to get a giant jack-o’-lantern,” he said.
This article appears in September 25 2026.

GREAT JOB HAROLD
Wow Harold!! That is really really cool. You did a great job. Congratulations
Bravo Harold ! Any interest in coming to talk about your pumpkin growing? The Garden Club of Martha’s Vineyard would love to meet you! Katie Dawson, 508 579 3284 or kmdawsonmv@gmail.com
Phenomenal! 400lbs could make for one intimidating jack-o-lantern!
I’m very impressed by Harold, his commitment, and his giant pumpkins! This is a very refreshing story!
What do you do with a gigantic pumpkin after you harvest it?
Harold, it was a pleasure to meet you with your parents in June and we are so very impressed by your passion for all things growing, especially pumpkins! Hoping your jack o’lantern brings everyone great joy…
Now that is news!!!.. Great Job Harold.
Most 13-year-olds are hoping to grow a few inches. Harold is growing pumpkins by the hundredweight…what a great kid and a great story.