Tuesday, January 8, 2013

Winter Vines: Why Vines Need a Rest, too.

You are in your Pajamas, it's 11:30 in the morning and you are watching bad television. It's cold outside and you can hear the cars in your neighborhood shudder as they are turned on. You've got your lunch on your lap. So what if it's a little bit early, it's winter and you are in hibernation mode.

Just like you, wine vines work hard for the rest of the season and become dormant in the winter. During this time cuttings are often taken from the mother root, and the vine stores up nutrients and hardens itself. Dormancy protects the vine from cold, and changes nitrate-nitrogen to arginine. You may think that the grapevine is at the mercy of the winter wind, but actually the plants need a sufficient dormancy period to produce quality fruit. In fact, this is such a problem in southern California that vineyards treat their grapes with chemicals to stop too early of a growth.

Grapes need anywhere between 250 and 800 hours of winter below 45 degrees to be at optimum for the growing season. (If you would like to read some more information on how to grow grapes in your own backyard while respecting the dormancy requirements of the plant, read here)
Another thing that is integral to the vine's health and production that happens in the dormant winter period is pruning. Annual dormant pruning removes the previous year’s fruiting canes or spurs (now two years old) and excess one-year-old canes. The fruiting habit of grapevines dictates a pruning practice that encourages the annual development of new fruiting wood. Fruit is only produced on shoots growing from one-year-old canes. Therefore, healthy new canes must be produced every year to maintain annual production of fruit. See the picture below for an example.

So the next time that you decide to watch all the Dune movies ever made, don't feel bad. Pour yourself a glass of wine,  and respect the rest that you both need and deserve.

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