Warming temperatures, lots of sunshine, Frisbee, golf, all sorts of signs are telling us that the winter is in the wake – mostly. Gardeners are anxious to start up the growing season and the temptation is great to begin the planning and planting for this year’s flowers and vegetables. But we are not necessarily out of the woods yet. The NWS hoisted a frost advisory Tuesday evening signaling the potential for killing frost. The temperature log for our weather station on Maxon Road extension shows that the mercury dipped well below freezing just a short while ago in the early morning hours. How can we be sure that a late frost won’t kill off our weekend’s hard work ? The truth is that just like any forecast model there are only probabilities of when the last frost might occur.
Cornell University Cooperative Extension has produced a map of the state with the average date of the last frost which is a good place to start. (insert here ?) We can see clearly the range of dates is quite large and it isn’t a south to north variation. What is noticeable is the fact that the earlier dates for last frost are found near bodies of water – the Great Lakes, Long Island Sound and to a lesser extent the Hudson River. Most of Albany County is forecast to begin the growing season around now while more than half of Schenectady County will have to wait well into May for good measure.
You remember from physics class that water bodies absorb heat more slowly but they lose heat more slowly as well. The effect will be more pronounced with larger water bodies but every little bit helps. Consider the Mohawk as a large sponge which will absorb temperature spikes and moderate the overall bouncing thermometer. Climate is defined as the long term average of temperature, humidity or rainfall but within local areas we can find variations which are called micro climates. If your garden is near the river it is a good bet that you have seen the last frost. If you are in the Niskayuna section it might be wise to wait a bit longer before planting the sensitive annuals. Those of us in Saratoga or uphill in Amsterdam will be wise to hold off a while longer.
Serious gardeners will keep records from year to year to help understand their local microclimate and help forecast these sorts of events It might be wise to start one now for the future.