Folks like us who garden or are in agriculture can get obsessed by frost. We know that the first frost is an important date. We understand that this first frost of a winter season heralds the end of the current growing season.
I called around the county to speak with a few gardeners and cattlemen. From Ann in Huntington, Stott in Hudson, Ian in Zavalla, and Jesse in Pollock, all reported that they’ve had some frost that has set back gardens and pastures alike.
I’ll never forget how some of our local gardeners that brag on getting fresh tomatoes into the onset of winter due to a late frost. They had to protect the tender plants from cold weather with a simple row cover, bed sheet, or other method.
Where did you notice your first frost? Was it isolated in the low lying areas of your field? Was it located down the hill in the lower part of the neighborhood? Frost will do that. It will find low-lying pockets where cold air settles and the temperature there can be a couple degrees cooler.
Urban areas have their own “heat island”. Brick and concrete and asphalt can absorb and hold heat, slowly releasing it as the evening progresses.
According to National Oceanic and Atmospheric Administration (NOAA) data, temperatures can range as much as three degrees warmer in the middle of an urban area where brick, concrete, and asphalt are found abundantly to the country where field and forest are going to dominate the landscape.
Look at any weather data site or grower’s data on weather patterns for this area and you’ll find our average first frost for Lufkin is mid-November. From a quick internet search for Angelina County, the internet will say anything from November 12 to November 20. I always hedge myself and tell folks ‘mid-November’ for this very reason.
Keep in mind that this is the average and recognizing it as an average is important. According to data kept by the National Gardening Association, we have a 10% chance of getting frost by Oct 29. On the other end, there is a 10% chance that we won’t get a frost until after Dec 2.
So, what really happens when we get a “frost”? When water gets below 32, ice crystals that form inside tender plants will rupture the cells and, effectively, kill it. Anything from 32 down to 29 degrees is generally considered a light freeze (or frost). Temperatures that dwindle down to the 28 to 25 range is expected to be widely limiting to most vegetation. Only a few native or well adapted plants will continue to grow with temperatures below 25. In years past, we have truly learned what were the toughest plants in our area as temperature went far into the single digits.
Just to be clear, there technically is a difference between a freeze at, say, 28 F and a frost at the same temperature. Water obviously freezes at and below 32 degrees F. But 28 F is the threshold for a hard freeze. “Frost” is officially when ice crystals form when moisture in the air is converted to ice without first becoming dew. Informally, a “frost” is any time the temperature drops to that 32-degree range, whether or not we see the ice crystals.
So, what garden vegetables can tolerate a light frost? The Michigan State Extension Service lists these as able to withstand a light frost: Beets, Broccoli, Cabbage, Carrot, Cauliflower, Celeriac, Celery, Chard, Onion (plants), Parsnip, and Radish.
Really cold tolerant plants that can sustain hard frosts below 28 F include: Collards, Endive/escarole, Kale, Kohlrabi, Lettuce, Mustard, Onion (sets and seeds), Potato, Rhubarb, Rutabaga, Spinach, and Turnip.
