Van den Heuvel excelled in individual challenges, including the Horticultural Biosecurity challenge and Avocado Tree Planting challenge.
Growers Emily Crum came in second place, while Megan Fox was third.
Van den Heuvel prize includes an all-expenses paid trip to Wellington to compete for the title of national Young Grower of the Year 2020 in August, as well as $1500 cash.
Chairman of the Bay of Plenty young growers upskilling Andrew Dawson said the passion shown by the contestants was what made the annual event so special.
New Zealand Kiwifruit Growers Inc. chief executive Nikki Johnson said that these competitions were an important highlight for the horticulture industry.
"The potential that Melissa and the other contestants have shown over the competition make me confident that the future of the horticulture industry is in good hands."