A three-year trial has shown it's reasonably simple to convert to organic wine production in Central Otago, provided there's the desire to do so and the financial backing, Gibbston Valley Wines (GVW) vineyard manager Grant Rolston says.
GVW, with Wither Hills in Marlborough and Mission Estate in Hawkes Bay took part in the national organic grape-growing trial.
The results will be presented at New Zealand's first national Organic and Biodynamic Winegrowing Conference, in Blenheim next week.
The study found that despite a few challenges the wineries all chose to maintain or expand their organic growing areas.
''We strongly believe this will give a better reflection of the site through the wines we produce from it,'' GVW winemaker Christopher Keys said.
For the trial, the wineries had to adapt half of their grapevines to organic production while a team of scientists monitored the results.
The other half of the vineyards were managed under standard wine industry agrichemical practices.
GVW converted part of its School House vineyard, which provided grapes - pinot gris and pinot noir - for its premium single-vineyard wines.
It now planned to convert the conventionally managed half to organic and change the pinot noir in its China Terrace, Bendigo vineyard to organic also.
Mr Rolston, of Vinewise Viticulture who contracts to GVW, said in a report the biggest challenge was weed control, as some of the vines had too much weed competition.
The biggest success was knowing they were managing the vineyard with minimal intervention, and were having little impact environmentally.
''This is resulting in quietly improving soils, improving soil biology and general vine health.''
The better understanding of the block meant they were able to address some problems to do with pruning, nutrition and water requirements.
''Increased soil biological activity resulted in reduced erosion, along with other benefits.''
Organic growing meant the management of the vineyard needed to be more proactive.
''Certainly one needs to be more observant and in tune not only with the vineyard but also with what the weather may challenge you with.''
He advised others looking to convert to not be afraid to take a step back to go forward and to seek advice from others already doing it to avoid making the same mistakes.
The trial was initiated by grower group Organic Winegrowers New Zealand, and funded by the Ministry of Primary Industries' Sustainable Farming Fund.
Jonathan Hamlet, of Organic Winegrowers New Zealand, said the monitoring results showed excellent disease control was possible with organic management.
''A number of the blocks showed it was possible, once organic management was established, to have equivalent production costs,'' Mr Hamlet said.
"The feedback from the winemakers involved in the project was very positive about the quality of the organic wines.''
