Flowering and vigour differences

By Max Marriott
Assistant Vineyard Manager, Gibbston Valley Wines

The second half of December has seen warmer, more settled weather finally arrive, with a string of days boasting maximums above 25oC. Flowering at our School House vineyard began in mid December, about ten days later than the previous year. The flowering has also seemed somewhat laboured, exacerbated by some overnight drizzle early on, with some inter-bunch variability evident. Some parts of bunches (pictured below) have set fruit, whilst other parts are yet to flower. The extent of this phenomenon will be better assessed post fruit-set.

The organic blocks are once again, like last season, showing a lighter green colour, bordering yellowish, on various parts of the vineyard when compared to the conventional blocks. We started the irrigation scheme for the season on an infrequent/soak basis (2hrs, twice a week, for example), but it soon became evident that the bonier parts of the vineyard simply had no organic matter to hold the water and so we reverted back to the frequent doses in smaller amounts (1hr, four times a week). It will be interesting to see the results of the petiole analyses come back from Hill Laboratories, but we suspect there will be some nitrogen deficiencies in the organic blocks – there is an obvious difference in vigour that is not due to water availability in the profile, but rather, is possibly due to root pruning from cultivation, lack of nitrates from weed competition, or other factors. We intend to apply a second (and possibly third) round of Wuxal Amino to these organic blocks to boost nitrogen levels.

Buckwheat emerges

We have had a good strike of buckwheat already, and now wait to see what the weather does over the coming month. Continued warm weather, with the odd spot of rain, will render the gamble of a late sowing a success.

Plans have also been made for the next field day, with a tentative date of February 12th. The focus for the day will be machinery, looking at a combination of undervine cultivators and mowers in action, along with a compost spreader and direct drill. We hope to see you there.