A busy weekend at our largest medical cannabis plantation

Harvesting has begun for 10 hectares worth of crop grown by medical cannabis company Puro - at Kekerengu on the Kaikoura coast.

The operation is unique for its organic growth processes that don't incorporate any chemicals.

Puro managing director Tim Aldridge says the weekend's harvest presents a significant milestone for an emerging New Zealand industry.

He says it's extremely challenging to grow cannabis without chemical fertiliser - an approach which gives his product a point of difference in a growing market.