By Jacqueline Maclaurin
Viticultural Technician, Wither Hills
Well what a season… as we hold our breath waiting for the endless summer to end, we anticipate the harvest of twenty thirteen.
The blocks are looking fantastic – with the end of February came the end of a busy few months – final leaf plucking, colour thinning and nets put on, just some of the tasks that have been keeping everyone busy.
The season has been a low pressure botrytis season to date, although powdery mildew has shown up in a number of blocks this season, both present on leaves and bunches. Due to the pressure of this we decided to tighten up our organic spray programme – a seven day sulphur (3.5kg/ha) and protector (500ml/100L) programme to protect new growth. The final spray was the 14th February prior to nets going on. Some powdery mildew has still shown up on new growth, but the levels are not of any concern.
Throughout the season the Sauvignon Blanc blocks have shown little difference in growth and timing of development between organic and non-organic regimes, following through to the first berry maturity sample with no difference in Brix levels. The canopy growth may have been marginally slower in the organic block, but no other differences from visual observation have been noted.
This season has again been challenging in managing the Pinot Noir blocks. With a visual difference in vigour this then follows through to crop loading and phenological development. The organic Pinot Noir has been behind the conventional block throughout the season, and the first maturity sample shows a difference of 1.5Brix, despite the organic block carrying a lower crop – 22 bunches per vine as a comparison to 28 bunches per vine in the conventional block.
We will continue to take weekly samples for maturity analysis up to harvest on all blocks and monitor vine health. The most noticeable difference in vine health has been in the Pinot Noir blocks. This season we have tried to focus on our inputs and timing of these, to increase the nutrients available to the vine, and so have given the organic Pinot Noir block an extra boost of nitrogen in the form of Wuxal Amino (5L/ha) as a canopy application on the 15th February.
We will collect soil samples in early May and make a plan for fertiliser inputs over the winter in the form of broadcast hard fert.
For the coming season we are looking at planting a cover crop to increase the vigour in the organic Pinot Noir block. Through discussions with Kiwiseed we have decided on a clover-heavy mix which will also contain grasses and herbs. The clovers to be utilised are crimson, subterranean and red clover. It is hoped that these plants will offer early spring nitrogen, whilst building organic matter in the soil and producing nectar for beneficial insects. Furthermore, plantain and tall fescue have been selected for their drought resistance and activity during winter. In addition a low rate of rye grass will be sown to help build the organic matter and build diversity into the sward.