With the growing season off to a cold start, I’ve been thinking about how to grow the best grapes in a cool season. Cluster thinning and leaf pulling can help by maximizing sugar production, in a grape vine, and by making the most of the sugar it produces. Good canopy management will bring out the best in a vine under all conditions, but it doesn’t work magic. Without enough heat, grapes won’t ripen well, and you can’t do anything about the weather. Or can you?
Scaling up a greenhouse
Jeff Chorniak inspired me to grow grapes in my suburban backyard and he used a collapsible greenhouse to extend the growing season. By sheltering his Cabernet Franc in this way, he made early spring and late fall just a tad warmer, and that can make all the difference when you’re growing grapes in Toronto. I’ve never done that myself, but the possibility of a cooler than normal season has me thinking about it. I’ve also wondered if the concept could be applied to a vineyard, by using plastic sheeting the way gardeners use row covers.
Some Puget Sound growers are doing just that. I’m hearing that overnight low temperatures, inside a tented vineyard row, are as much as 10F (5.5C) warmer than neighboring untented rows. On a clear day, under bright sun, it can get up to 15F (8.3C) warmer. “As much as” and “up to” are always tip offs that typical performance will be less, and that’s probably true here. Still, every degree helps and this might be a good way to cope with a cooler than normal year.