November and Our First Frost

WHERE’S THE COLD WEATHER?

Here we are in early November and experiencing a nice warming trend. Yes, we have had some cold nights with temperatures down into the low 40s and upper 30s. And, yes, some of you have experienced a frost. But most of us in the Richmond area and surrounding suburbs have yet to have our first killing frost. Many of us still have summer annuals such as impatiens, vinca, marigolds, etc.; they are happy and blooming. In addition to this warm trend is our rainfall. To date, we are very dry. Our last decent rainfall was on October 3rd. We have not had any rainfall since. So, we are dry. We need some rain.

People ask me if they can still plant shrubs and trees. The answer is yes. Now is still a great time to plant. As of October 25th, our soil temperature is 53 degrees. All I recommend is that you make sure the plants are well watered before planting, water the plants as you plant, and don’t let them dry.

October 20th is the average date of our first frost of the fall season in Central Virginia. We are now well beyond this point. Only Mother Nature knows when we will have our first frost.

Frost is caused by radiational cooling. This occurs on a calm and clear night when heat from the earth radiates upward into a cloudless sky. As a result, the soil and plant surfaces and the layer of air near the ground cool. If the temperature drops below 32 degrees, a frost occurs. On a windy night, the warm upper air mixes with the cool lower air, and frost is less likely.

On a warm, sunny fall day, our soil will absorb heat. It releases this heat at night and can warm the plants by several degrees—enough to save tender plants on a frosty night. One gardening practice that helps protect plants is using water. If our soil is moist, it will absorb heat from the surface down several inches. Dry soils do not conduct heat well. Another gardening practice to protect our plants is the use of mulch. Mulch will act as an insulator of heat during the day and release this warmth at night.

Do you ever wonder why farmers use a sprinkler system at night to protect their plants? This practice works because water gives off heat as it freezes.

So, adding some mulch around plants now is a good gardening practice. And be sure all plants are watered if frost is in the forecast. In the Piedmont region, which is Central Virginia, we are now in “peak week” when it comes to leaf color. Trees with leaves protect plants below from damaging frost.

Eventually, cold temperatures will set in for the season. But until this happens, our soil temperatures continue to be warm, allowing for a great fall planting season as we get ready for the Holiday season. So, don’t stop planting just because of the calendar month. Now is a fantastic planting season.

PLANT A LITTLE NOVEMBER HAPPINESS!!!!

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