The small West Coast town of Hari Hari is home to the largest eggplant-growing business in the South Island. Every week, depending on the season, Glen and Janna Monk send up to a thousand crates of the vibrant purple fruit over to Christchurch.

Photo: RNZ/Cosmo Kentish-Barnes

The Monks' eggplant operation is set up on a dairy farm just south of the Hari Hari township, which is between Hokitika and Franz Josef.

They employ eight staff, making them the second largest employer in the area after the local area school.

Their team grow eggplant vines – each producing about 50 fruit a year – and chillies in glasshouses spanning 7,500m2.

Once an additional 2500m glasshouse is up and running, staff numbers are likely to double when production reaches its peak during the summer.

Photo: RNZ/Cosmo Kentish-Barnes

Despite the area's low population, finding local staff hasn't been a problem, Janna says.

"We've only ever put a quick message on Facebook for staff. Normally, people come to us, it's the way the community goes. They'll get in contact and we'll see if they're the right fit for what we're doing here and go from there."

Photo: RNZ/Cosmo Kentish-Barnes

The glasshouses are heated by coal-fired boilers and heating, along with staff, is the biggest expense for the Monks.

They're currently looking at other ways to heat the water pipes.

Janna believes the most promising alternative is geothermal energy.

Just down the road at Whataroa, scientists have encountered water hot enough to boil at 600 metres under the ground.

Their property is only five kilometres from the Alpine Fault, and a feasibility study is underway to determine whether it's possible for them to drill down to geothermally heated water underneath.

"We definitely want to find a way forward so we can get into it somehow," Janna says.