When former banker Tony Boswell bought Windermere Gardens in 2011 it had been out of business for a year and parts were in weeds.
The next year the crops made $522,000. The year after that it was $833,000. This year it will be $2.75 million, and $3.25 million the year after that, Boswell said.
"The way it was being done, it doesn't work any more. It's a different farm, in the same place."
However, Boswell is now looking at other options with the business on the market.
The business, now known as Windermere Farms, is on 10ha of Westmere loam on the western outskirts of Whanganui. It used to be a place where students got school holiday jobs.
These days it has 36 tunnel houses growing strawberries, raspberries, blackberries, boysenberries and blueberries. The tunnel houses get to nearly 40C on a hot day and have vents to cool the workers.
Picking starts at 7am during the hottest part of the year, and finishes at 3.30pm.
"I have a damn good staff and they have to be looked after. They're the lifeblood of this place. They're amazing," Boswell said.
Only one patch of strawberries still grows in the ground. That is uneconomic due to labour costs and will be gone soon.
On February 22 there were 50 people working at the farm. This year just nine of them were school age, and they claim their jobs in the September holidays. For the last four years Boswell has had teams of Samoan workers, who want to come back.
During the summer peak there were 124 staff at the farm.
Its cafe is getting busier. On a weekend day it can have 1000 customers. Last year it was closed for seven weeks due to Covid-19, losing $85,000 in income.
Boswell still allows people to pick their own berries, even though it's a loss-making side of the business. He is from Whanganui and keeps it going as an "institution", and because children love it.
The farm's spring water, which previous owners sold as drinking water, is now used to irrigate crops. Previously the farm relied on rain and crops failed during droughts.
Boswell has built a refrigerated berry packhouse, one of three in New Zealand. The temperature inside is 9C, and staff work in beanies and polar fleeces.
The key to the farm's success is its highly qualified growers, and Boswell especially relies on two. Much of their work is done online and they have introduced new techniques and higher-performing cultivars.
Raspberry production, for example, has increased from six tonnes per hectare to 23 tonnes.
For three years Windermere exported berries. But the pandemic stopped that - berries travel in wide-bodied passenger planes and fewer are flying.
Winemaking didn't interest Boswell, but he thought if the farm made wine it should make it well. He hired winemakers, who entered their raspberry wine in a competition. The wine won the gold medal for raspberry wine, a gold for red wine and was the overall top wine in the show.
Boswell is selling the farm now because it is getting bigger. It could grow further if it had more land. It is very much a full-time job.
"I can handle it this year, but I can't handle it next year."
He expects to spend the next year working alongside the new owner, and wants to leave that person something they can add to the business.
He's not sure what he will do after that.
"If you keep your ear to the ground, an opportunity of a lifetime turns up every 12 months," he said.