I have not seen a frost yet this year. And even though I was out of town during a cold spell just before Thanksgiving, my tender, tropical Canna lilies tell me they’ve not been touched yet by any freezing temperatures.
Now, I have some friends to the north of me that have certainly reported the first frost of the season, but as for me and my farm, I have not seen the first frost.
First frosts are a major marker for agricultural producers, gardeners, and landscapers. A frost effectively ends the growing season for several warm season annuals and puts many perennials into their winter slumber.
Historically, the average first frost for our area is mid-November. A couple of years ago in 2019, we had a hard freeze on November 1– a full two weeks ahead of the anticipated average frost. Records from the weather station at the Angelina Airport in Burke indicate the first frost in 2020 to have occurred on November 30.
But here we are, almost midway through December without any real cold weather. Except for a close call over the upcoming weekend, my 15-day forecast doesn’t show any signs of temperatures dipping to or below 32 F up till Christmas Eve.
So, what really happens? 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. Last year, we 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. “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.
I wonder how many gardeners might still be able to harvest warm season vegetables with this mild, mild start to winter. In the past, I’ve known gardeners to enjoy tomatoes from their own garden on Christmas day. Surprisingly, tomatoes can survive a light freeze if it is not accompanied by frost, provided temperatures don’t dip below 28 F.
I’m betting there will be a few enjoying them this year if they have cared for their fall gardens long past their typical production times.
Frost also matters to livestock producers because it ends the growing season of their warm season pastures. If pastures can still provide grazing for livestock, then stockmen can delay the feeding of hay and hay is one of the biggest expenses of the year.
As I write this earlier in the week to make the deadline for publication, I may be proven wrong and temperatures dip low enough this weekend for us to have our first frost. My weather app, however, is currently indicating that no such cold weather will occur for the next 15 days.
Now, the weather forecasters ‘always’ get it right, don’t they? You can bet I’ll be looking at my thermometer and getting outside early in the morning to check for our first frost.
Cary Sims is the County Extension Agent for agriculture and natural resources for Angelina County. His email address is firstname.lastname@example.org.
Educational programs of the Texas A&M AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age, national origin, genetic information or veteran status. The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.