Consider the combination of high and low temperatures that is being reported we (and our plants) are about to receive:
- Today: 45 and 27
- Friday: 41 and 25
- Saturday: 41 and 25
- Sunday: 41 and 23!
In New York City, the nearby ocean, the moist air, and certainly the time of year, influence the temperatures. When our temperatures are in the forties for highs, the sky cloudy, partly cloudy, rainy, damp, the fluctuation between high and low has been, from what I remember, not significant, maybe 10 to 15 degrees. In fact, the average for these dates run about 45-53 for highs, with lows around 30-37.
Last year, however, March 27th (this Sunday's date) had temperatures between 44 and 29 degrees F. Although colder than average, this is within the 15 degree fluctuation and with a low that is less troublesome at 29 degrees. This Sunday's low of 23 degrees makes for a temperature fluctuation of 18 degrees, which as numbers go, is just a few more than the usual 15. But three degree difference means that our tender, young plants will spend many more hours freezing, and, by my classification, makes for an unusual temperature event.
I have already raked up the leaves, transplanted perennials, and planted frost-hardy vegetables. Only now do I understand why a fabric row cover that provides only two degrees protection can become a highly useful tool in the field. So consider this -welcome any snow that falls and remains over the next several days. One, two, or more inches of wet snow will help to protect emerging plants from several hours of freezing much like a row cover does -but possibly better.
Update: Weather Underground has been slowly upping the low temperature forecast, but also lowering the high, so that now the temps lie squarely within the average 15 degree fluctuation. No matter, they're now saying we have a low of 25 on Sunday, which, believe it or not, is considerably better than 23!