Have you noticed the warm weather? If you live in Maine, or some areas in the Pacific Northwest, you may have not (sorry Alaska, you are excluded from these regions based on distance). For the rest of the 48 United States, there has been significant warmth for the month of February.
I live in Southeastern Pensyltucky as I like to say. For the non-geographical folks, that means outside of Philadelphia. This past weekend, there was three days of warm temperatures above 60 degrees with highs into the 70s. For Thursday – Sunday of this week, there will also be highs into the 70s. This weather and prolonged warmth is unusual for our area. I have noticed that the Philadelphia region has some of the most boring and standard weather around. There will be days of cold, then days of mild temps, then back to cold-in the winter at least. This regular ho-hum weather temperatures are not heard of elsewhere. In other areas of the country, the temperatures change day to day. My friend in Dallas Texas reports days of 75 degrees and sunny with the following day cold and 33!
Being interested in viticulture, or the growing of grape vines, I tend to monitor the temperatures around the year. Some winters, I look out for extended cold temperatures, since I don’t want the raw cold to destroy my vines. Other times, like this past winter, I watched for these extended warm periods similar to the one we are having this week. I am worried that the April temperatures that we are experiencing in February are going to really screw with my grape vines. Most plants need so many thousand hours of “chilling” before they are cued to regrow in the spring. Some plants’ chilling hours are satisfied by being below 50 degrees. Others, such as grapes, are satisfied being chilled below 40 to 35 degrees. This doesn’t mean that the vines are destroyed from lower temperatures, as all it means is that after so many hours below the chilling temperature, the vines are ready to break their dormancy and emerge for spring time.
In southeast Pennsylvania, we have a moderate type of winter. The winter is long enough to easily satisfy grape vine chilling but not too short or either too long. It is just the right length. In fact, since similar grape varieties grow in Virginia and North Carolina, one can deduce that the required number of chilling hours for the same vine in Pennsylvania will probably be satisfied around late January to mid-February. Hence my concern for this early warming period we are feeling now. The vines in my area have already satisfied their needed chill requirement. With the continued warm temperatures, they may eventually emerge with new leaves. This is a concern because March weather is erratic and wild, with some late freezes and at other times mild wet and rainy days. If a late freeze occurs, small grape flowers will be ruined, forcing the vine to use its secondary, later flush of flowers. Those secondary flowers are not as numerous as the first flowers, which limits the number of potential grapes to grow.
For many folks, the warming time is the beginning of spring fever. It is a needed relief from a cold and raw winter. In fact, I don’t mind it either! I even wore shorts and a tee shirt today when taking my dog for a walk. The weather was pleasant, the air smelled fresh and the birds were singing/tweeting ferociously. On Wednesday I saw a few forsythias and flowering pears with the beginnings of flowers. I really do enjoy this break in the weather, but as a grape grower I enjoy it with a side of noted caution. Happy early Spring.
The world is an ever changing place