His shiny, orange 200.5kg beauty was the biggest the annual competition had ever had - 60kg heavier than the previous record.
It grew out of a compost heap beside his Mangamahu Village house, Jimi said.
And his secret: he watered it with a sugar solution, an idea he got from a cousin.
So it was Jimi who went home with the shield. There were three other awards, one for the biggest new entrant, one for the average weight, and an ugly garden gnome for the biggest loser.
The competitors were in relaxed mode when the Chronicle called, chatting in the sunshine over a shared lunch, and getting ready for the children's Easter egg hunt.
Mrs Firmin said the Pumpkin Off was in its fourth year, and the idea came from herself and neighbour Jane Atchison.
They thought people needed "some fun with no good reason" after the grim years recovering from the 2004 flood.
They put the idea out to the valley's 50 to 60 families and had six entries in the first year and 20 this year. Atlantic Giant pumpkin seeds are given out on Labour Day and planted after that, and the fruit are always judged around Easter.
Secrets of pumpkin raising are closely guarded, but usually involve various kinds of manure.
The pumpkins are getting bigger every year.