Monday, May 17, 2010

Frost Damage on the Grape Vine



I am beginning to struggle every year on when to plant my garden. I normally would plant in the beginning of May.  Now I begin to plant later in the month due to losing my crops to frost around Mother's Day.  This is nothing compared to what many of the farmers face this time of year. This past week parts of the Hudson Valley were hit with a devastating frost.  Some vineyards were hit hard.

Frost damage happens when temperatures drop below 32 °F after green growing tissue has appeared from a bud. The vine is in danger when the first green growth produced on a new grapevine shoot is two or three basal leaves, immediately followed by the embryonic flower clusters that will become this year’s crop. Many times the temps need to fall below 28 °F for the vines be severely affected, as in the case this past week.

Frost damage occurs due to the freezing of plant cells. As freezing occurs the ice expands rupturing cell walls, disrupting membrane function and irreversibly denaturing enzymes by dehydration.  Mild frost injury may appear only in the death of a few leaf cells. Leaves affected have pale yellow or clear, mottled areas within their veins. Some tissue may eventually become necrotic, causing leaf distortion and have the appearance of dead leaf tissue. More severe frozen leaf tissue becomes soft, brown and limp.

Carlo Devito of Hudson-Chatham Winery was hit hard with last weeks frost.  Here's what he has to say to YNN reporter Beth Croughan.  Click Here.




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