Compost, sowing beneficial plants… and frost

By Grant Rolston, Vinewise Viticulture

Budburst occurred as predicted around October 5th. We spread compost in the organic vineyard at budburst. Ideally this would have been done in Autumn or a bit earlier in spring. Difficulty in locating a compost spreader delayed the timing.

Spreading compost in the organic block

We made compost from our 2010 grape marc; we added rye corn straw, some rotting hay and cow manure, which was turned four times, and the resulting compost was of good consistency to spread. We decided to spread this under the row and then immediately mound over with the Braun mounding discs. We feel this method of incorporation with the soil allows the best use of the compost, especially coming out of a herbicide regime. The microbial boost in the under vine area (previously herbicide strip) should be beneficial in biologically regenerating that soil.

We had received very little rain over the preceding months – just 5mm for August and 5mm for September. This was the driest spring for some years. Nevertheless, we decided to sow a buckwheat and Phacelia mixture, crossing our fingers for some rain to help with a good strike. Buckwheat and Phacelia are preferential food plants for a parasitic wasp that lays its eggs in the leafroller caterpillar. With different flowering times, this provides a larger overlapping window for natural biological protection from leafroller infestations.

Buckwheat

We applied the buckwheat seed at a rate of 45kg/ha and the Phacelia at a rate of 5kg/ha, sown on a strip 1.2m wide (every tenth row) down the middle of the row. We received 6mm of rain on the 14th and a further 30mm three days later, and a great strike resulted.

We commenced our canopy spraying regime at budburst and observed steady but certainly not spectacular growth during October.

We hosted a field day the first week in November which was attended by around 50 people. Dr Tim Jenkins spoke on his associated project studying soil biology and soil structure in the vineyard. All those present certainly know a lot more about worms, their activity and importance in our soils. Other subjects covered included mychorrhizal fungi, grass grubs, etc. Thank you Tim, this was a very interesting session.

The buckwheat and Phacelia were looking great until — Bang!! — on the morning of November 5th we certainly had fireworks.

A very unusual weather event occurred with intermittent snow falling in the vineyard. In between snow showers the wind would drop and frost conditions prevailed. A cold blast of air must have swept down off the hill and caused some damage through the middle of the vineyard. The damage varies from very minor (an odd leaf here and there) to moderate, with some tip burning and possible bunch damage. Luckily we had not yet shoot thinned, so have been able to mitigate a lot of the damage through selective shoot thinning.

This site had not been frosted previously so we opted not to frost fight.

The buckwheat is looking very sad, however we look forward to the end of the frost season; for us December is safe. Roll on Summer.

Conventional block on 26 Nov

Organic block on 26 Nov