DEERFIELD — A New Hampshire man set the record for growing the biggest pumpkin in the world at the Deerfield Fair on Thursday, but was only to be king for a day as some giant contenders hit the scales at other fairs around New England.

Steve Geddes, a grower of giant pumpkins from Boscawen, brought his massive squash to the weigh-off at the Deerfield Fair on Thursday evening, and based on its measurements, everyone guessed it would total around 1,600 pounds — a big pumpkin for sure, but not a world champion.

“What a surprise for everybody when it hit the scale,” said Jim Beauchemin, a giant pumpkin grower from Goffstown and the MC for the pumpkin weigh-off.

Geddes' pumpkin weighed in at 1,843.5 pounds, besting the world record of 1818.5 pounds set last year by a pumpkin grower in Canada. Beauchemin said that by “taping” or measuring the dimensions of a pumpkin, growers can estimate how much a pumpkin will weigh, and based on those numbers, Geddes' pumpkin appeared to fall into the 1,600-pound range. But taping can't account for the thickness of the walls of a pumpkin — the thicker they are, the heavier the gourd — and that can mean the difference between a good pumpkin like Geddes thought he had, and the great one which it turned out to be.

“It was great to see a world record-setter at Deerfield Fair,” said Beauchemin. “Deerfield has only been doing official weigh-offs for four years, so it's really neat that something like this would happen here.”

But Geddes' victory turned out to be short-lived. According to Beauchemin, a father-and-son team has taped two giant pumpkins at 2,000 pounds. The measurements were spot-on. Ron Wallace of Greene, R.I., had a pumpkin weigh in at 2,009 pounds at the Topsfield Fair on Friday night.

Still, Geddes' pumpkin will likely remain New Hampshire's largest pumpkin for 2012.

“Most all New Hampshire growers were [at the Deerfield Fair] last night and I don't think anyone from New Hampshire will beat it,” said Jim Demers, president of the New Hampshire Giant Pumpkin Growers Association.

Geddes unseated Bruce Whittier of Henniker, whose giant pumpkin broke the record for New Hampshire, hitting the scales at 1,593 pounds at the Topsfield Fair in 2011.

nfoster@newstote.com