Preparing for winter

As temperatures drop and the days get shorter, grapevines prepare themselves for winter. Leaves and buds are isolated from the plant’s vascular system, becoming dehydrated, protecting the vines from frost damage. As further protection, sugars and proteins accumulate, bringing down the freezing point of contained water. By doing this, vines can survive winter temperatures as low as -20° Fahrenheit! 

Important work

Once the leaves have fallen from the vines, vineyard crews take on the important task of winter pruning, trimming the previous season’s growth to control yields and vine health. Without this vital work, the vines would produce too much fruit (reduced quality and longer ripening time), be more vulnerable to mould (less airflow), and prone to uneven ripening (poor light penetration). With roughly 140 acres planted and around 800 vines per acre at Sculpterra Winery and Sculpture Garden, that means over 110,000 vines require individual attention! Where would we be without our hardworking field crews?

I dare say it comes as a relief to Sculpterra’s own small number of field workers that many of those vines are leased out to other growers, leaving ‘only’ around 28,000 for them to deal with.

Some vine anatomy

Above ground, winter vines consist of four main parts:

• Scion / Trunk – The first year’s growth to the fruiting wire.
• Cordons / Head (depending on the training method) – Growth from the first/second year, trained along the fruiting wire.
• Spurs – Older, lignified growth on the cordons or + from which shoots grow, becoming canes.
• Canes – The previous season’s fruit-bearing growth.

What’s involved?

Each cane is pruned back to 1-3 buds, controlling how many new shoots will grow in the following spring. The number of buds left will vary depending on the health and vigour of each vine, as well as the yield required. If for any reason a cordon needs replacing, a selected cane can be tied to the fruiting wire to eventually replace it. Any part of the base of the cane that is left will become part of a spur. Occasionally, a cane is left deliberately untrimmed, this is known as a ‘kicker cane’. By diverting some of the vine’s energy early in the growing season, kicker canes help to moderate vigour. Great care is required to ensure a balanced canopy during the growing season and obtain maximum fruit quality.

Petite Sirah vines before and after pruning

I certainly learned a few things while researching for this post. I hope you enjoyed reading it.
Darren.

Sources-

Paul Frankel, Winemaker at Sculpterra Winery

Cornell University College of Agriculture and Life Sciences 

Grape Growers Handbook, Ted Goldammer

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