OCTOBER ROLLS ALONG and this past week saw temperatures dip into the 40s at night in many locations in Jefferson and Clallam counties. Soon we will welcome back Jack Frost!
Some plants are more tolerant of frost than others. Woody plants are less affected than succulent plants. Fruits and flowers may be more sensitive than leaves. Plants already exposed to cool temperatures will be more resistant.
Within your backyard, you’ll probably find variations on different sides of the house, under trees, on south or north facing slopes or low laying areas.
Cool air settles at the bottom of slopes because it is heavier than warm air. Frost pockets will then form in valleys where cool air becomes trapped. Hilltops are also susceptible to cool temperatures. Hillside’s often remain frost free until a more severe frost occurs.
How to protect our plants? Plants always killed by frost include your summer annual flowers and vegetables such as impatiens, coleus, marigolds, tomatoes and peppers.
There’s no point in trying to protect these; simply replace them next spring.
Any tender house plants that have been growing outdoors need to be brought inside. Check the plants first for aphids, ants or other pests to make sure you don’t include any uninvited guests.
Some plants love winter, which enable us to have flowers in our garden all year. Pansies, violas, snapdragons and ornamental cabbage and kale laugh off the frost and provide us with color in the gloomiest months.
Cyclamen is especially bright and rewarding. It’s a bulb that blooms in bright red, pink, and lavender tones throughout the winter and early spring.
Here are my three ways of meeting frost.
Trick No. 1: When you believe it’s going to freeze, water your garden to saturation. Make sure you see some puddles. Moisture in the ground tends to prevent warming of the ground during the day. It also tends to prevent a large fall in temperatures during the night. When dew point is reached, the latent heat given up by saturated soils checks the rate of cooling. If a hard frost is moving in when the abundance surface moisture freezes, the liberated heat from the water checks the falling air temperatures.
Trick No. 2: Covering is the most effective anti-frost to most people. Covering plants the night before with the sheet, blanket or tarp will trap the warmth from the soil over the plants preventing freezing. Covering will usually protect plants when temperatures drop into the upper 20s. Plastic used as a covering usually doesn’t work as well as the other coverings mentioned. Fortunately, first few frosts are usually accompanied by several weeks of nice weather and one only has to cover for a couple of days. Now is the time to prepare the areas you need to cover. Drive any kind of stake next to your plants, since coverings that lay directly on the plants crush them. I have seen numerous times where the plant was saved from the frost, but the weight of the dew-soaked sheet ruined the plant. Also, having an air gap around the plant helps trap the heat of the ground and is superb insulation.
Trick No. 3: Sprinkling plants with water is often used as a “morning after” solution when there’s a light frost (28 to 32 degrees). I know it sounds crazy that it will actually protect the plant from frost damage, it does work. When water cools and crystallizes into ice, heat is released which may prevent internal damage before freezing occurs within plant cells. The time when the internal plant temperature is coldest is in the morning.
If the drop in temperature is not too great (more than a few degrees), soaking your plants to dripping wet — before or at dawn — may protect tender plants that were left uncovered.
And please, protect yourself by staying warm and staying well!
Andrew May is a freelance writer and ornamental horticulturist who dreams of having Clallam and Jefferson counties nationally recognized as “Flower Peninsula USA.” Send him questions c/o Peninsula Daily News, P.O. Box 1330, Port Angeles, WA 98362, or email firstname.lastname@example.org (subject line: Andrew May).