Southern Spring: frosts, sward, and sowing

By Max Marriott

Assistant Vineyard Manager, Vinewise Viticulture

Despite an early budburst in Central Otago, time and growth seemed to almost stand still as cold, wet, dreary weather descended during October. By the end of the month, there were predictions that we were almost two weeks behind, which was exacerbated by the cold snap and frosts that hit the region in early November. Fortunately, damage to the School House vineyard was only very minimal, with the odd burnt leaf and stunted shoot – you had to look hard to find any damage at all. Very fortunate when compared to the devastation that occurred to other vineyards across the region. Grant made the call to have a helicopter on standby – for the Saturday, Monday and Tuesday nights – and without this the picture would have been far grimmer. The chopper was used on the Saturday and Monday nights (early Sunday and Tuesday mornings) and temperatures were kept above freezing. For a site labelled as “frost-free,” it just goes to show what nature can turn on, having suffered from an advective frost event the year before and fighting against a radiation frost this year.

Organic sward develops

The recent field day – though held indoors, not at the vineyard – served as a good refresher and provided outlook for the season ahead. This included a revision on botrytis, given the season we’d just had, and this highlighted some useful reminders about canopy management, infection periods and prevention. As far as the seasonal plan is concerned, there won’t be a lot of changes up at School House. Some of the organic blocks were pruned slightly more aggressively over the winter as a reaction to the reduced vigour from the first year of conversion. With this influx of spring rain, it’s been interesting to observe the flush of growth through the inter-row sward and acknowledging the different species that seem to be emerging in the different blocks. Though only early in the game, there does appear to be a shift in the organic blocks to different (and more diverse) inter-row species.

Given the impact of spring frosts on our buckwheat strike last year, Grant made the call to delay cover-crop sowing this year, which in hindsight (after the November frosts), was a great call. Now as we move into the first week of December and drill our phacelia and buckwheat, it will be interesting to see how well they strike and how well they tolerate the drier conditions as we head into summer. It should serve as a good comparison in any case and with any luck we’ll have both flourishing post-flowering and pre-bunch closure, providing habitats for all of those beneficial insects.

Fertigation and spray regimes remain consistent with last year (both in frequency and type). Subject to how the season progresses, we may have to utilise an extra weed spray and undervine cultivation (for conventional and organic respectively) if this wetter weather continues.

Experimenting with later sowing of beneficial crops in the inter-row