Does it mean I’m acclimated to the cold if I’ve stopped looking at the thermometer every morning? I moved to Fairbanks and started my job as horticulture agent for UAF Cooperative Extension Service right after Thanksgiving.
During my first two and a half weeks here, the temperatures never rose above zero degrees. It’s a good thing I’m not a plant. Dramatic temperature changes, especially over a short period of time, wreak havoc on a plant’s ability to survive. After three decades of living and working 360 miles to the south, the cold was a bit of a shock.
To acclimate means to adapt or become accustomed to a new climate or environment. Perennial plants need to acclimate to the cold if they are to survive winter. Those that are winter hardy do so each fall. Shortening day length and gradual exposure to colder and colder temperatures help induce hardiness as do changes occurring within a plant’s cells. Changes in lipid and protein composition in cell membranes enable plants to withstand freezing temperatures. These are changes to which I can personally relate given winter is a time when I crave more protein and have a tendency to put on more fat.
Plants able to survive the winter also have the ability to suppress ice formation within their cells through a process called supercooling. However, the lower temperature limit for this mechanism is 40 degrees below. At or below this temperature, ice crystals form spontaneously and plants living in this environment must be adept at tolerating gradual dehydration to prevent freezing.
To adapt to my new Fairbanks environment, I’ve added layers of clothes, changed fabrics and figured out I need gloves inside my mittens. Unfortunately, I think I’m also going through gradual dehydration, but unlike properly acclimated plants genetically programmed to survive 40 below, gradual dehydration is not part of my survival strategy. I need to drink more water.
A warm spell in January is tough on perennials, but cold hardy plants really suffer later in the season. As daylight hours lengthen and temperatures warm, plants begin to de-acclimate. This is the time when winter injury commonly occurs. If plants are in the process of losing their cold hardiness or are no longer dormant, an unusual stretch of warm weather can result in cracked bark, injured roots and dead buds.
Unlike overwintering perennials, I do not go dormant during the winter months. I am always anticipating spring and have been busy planning. Registration is now open for the Fairbanks Master Gardener course, which starts Feb. 9. Classes meet Tuesdays and Thursdays from noon to 3 p.m. Pesticide applicator training classes will be available in January and again in April for farmers and those who apply pesticides commercially.
If you’ve enrolled in the Fairbanks Garden Club’s Landscape Design School, I’ll see you during the session on design and maintenance. I’ll be teaching classes for new community gardeners as part of the Fairbanks Soil and Water Conservation District’s project to develop community gardens in South Fairbanks. Gardening classes will be held during Extension Week, beginning April 10. Watch the schedule for Powerhouse Veggies, which will cover the vegetables that are the most nutritious to grow. Plans are also underway for a Junior Green Thumb Gardening Camp during UAF Summer Sessions.
I am happy to be in my new environment at 65 degrees north latitude. I’m not leaving for Hawaii, but if I did, readjusting to the cold would not worry me. If I was a plant, however, subjecting myself temporarily to 75-degree temperatures could cause serious problems, especially if my chilling requirement had already been satisfied.
I will attend the Alaska Peony Conference in January and the Alaska Sustainable Agriculture Conference and the Delta Farm Forum in February. Please come introduce yourself if we haven’t already met.