When Brodie MacDonald decided to get married, he spelled it out for his fiancée. In potatoes. On his future in-laws' backyard.

MacDonald had hinted about getting married before, telling Olivia Harris he knew what he wanted to do last Christmas. One afternoon in September, he told Harris they were going to spend the day with her family in Springfield West, in western P.E.I.

I love you more than all of the potatoes in O'Leary. — Boyfriend writes in future fiancée's cards

He walked her to the backyard, and suddenly that Christmas pledge became real.

"In the grass, he had written — in potatoes — 'Olivia will you marry me?'" Harris told CBC Radio's Island Morning.

It wasn't a half-baked or even twice-baked idea. Harris quickly said yes.

"He made some fibs to me the day before. He spent the day with my parents and my sister," said Harris, who learned later most of her family was in on the plan. "He was hemming and hawing and putting his hands on his face to make sure they were all in the right place."

Brodie MacDonald and Olivia Harris plan to get married in September. (Olivia Harris/Facebook)

'It was very special'

As it turns out, it takes about 200 potatoes to spell out a marriage proposal, and September isn't the best time of year, as most warehouses are empty, waiting for the new harvest to come in.

"I think he took the very last ones. That was OK with my dad, I'm pretty sure," Harris said with a laugh. "I think he had to make a few trips."

The Harris family has been running a potato-growing operation in the western P.E.I. community of O'Leary for several generations.

Potatoes have been more than a side dish during the couple's relationship.

"He's always written on all of my cards, 'Olivia, I love you more than all of the potatoes in O'Leary.' Coming from a farm family, that was very important to me," Harris said.

"Brodie even took my father to pick up the engagement ring. It was very special. My entire family were around and we went to visit everyone afterward."

The newly engaged couple took to Facebook to announce their mash-up, which caught the attention of the PEI Potato Board, the marketing organization behind the province's 37,000-hectare potato crop.

"I'm very proud of where I come from and I'm very proud of what my family does, and what a lot of Islanders do," Harris said in accepting the board's proposal.

The board wrote up and posted a piece in the Buzzfeed Community section, as an unplanned part of its marketing plan.

During a year that has seen the board dealing with multiple reports of food tampering, the potato proposal was a story it wanted to share with the world.