NOW THAT AUTUMN is here, cold weather will soon be upon us, and Jack Frost will come to visit your yard. These first few frosts of the year taunt me.
My aggravation stems from the fact that usually after the first few frosts of fall, nice weather returns. We even give it a name — Indian summer. Also frustrating is that a few simple tricks can prolong your blooming plants’ beauty well into November or keep your veggies on the table until late autumn, but we often forget them until after the frost.
Before it’s too late this year, let’s tackle those tasks.
Black and white frosts
The most important thing to remember is that heat always gives itself up to cold. Whenever adjacent objects have different temperatures, the colder always gains heat at the expense of the warmer. At night, the Earth loses its radiant heat from the sun.
This time of year, if a cold front passes through and enough heat is given off to the air, the surface temperature drops below freezing (frost). When humidity is high and the night temperature is below dew point (temperature at which the relative humidity equals 100 percent), but above freezing, dew forms. You can see heavy dews in October actually greening the grass.
When night temperatures drop below freezing and below the dew point, a white (hoar) frost forms. If the air temperature is above the dew point but below freezing, a black frost occurs.
Black frosts we fear. Not only do they spin our cars out of control but also heavily damage plants due to freezing of internal plant leaf tissue. Black frost can be lessened by keeping soil moisture high.
Frost can follow almost any type of weather, since it is a function of heat. It becomes more likely as fall progresses and soil temperatures drop. Frosts are especially likely on crystal-clear nights in the coming weeks, when a cold front passes through.
So what can one do to protect the bountiful yard from the ravages of frost? First and foremost, moisture and humidity are your best natural tools. Although watering the ground tends to prevent the ground warming during the day, it also prevents a huge fall in ground temperature during the night. As the dew point is reached, the latent heat trapped in the water is given up and checks the rate of cooling. Even if the surface moisture freezes, that liberated heat also checks the temperature falling rate.
When the ground is dry, humidity is decreased, dew point is lower and the more damaging black frost can occur.
Bring plants inside
Water your garden heavily on suspected cold nights. Bring your movable plants indoors. Put hanging baskets, pots, containers and window boxes in the garage, under the carport (against a warm wall) or on the porch. Put them out again in the morning and bring back undercover when cold nights are predicted.
Cover your plants
Use old sheets, tarps, blankets or colored plastic. Remember, we are losing heat radiantly, so clear plastic, although trapping some heat, still allows plants to freeze. The most important fact to remember when covering plants is that dew-laden plants or wind-whipped blankets and sheets protects the plant against frost, but bust the heck out of them.
Be certain to go out in the next few days and prepare the area for cover. Drive down stakes, pound in poles, hang wire or rope and gather rocks, so as you hang the cover over the plants, it will be suspended over them and held down.
Water, water, water
Finally, and only if, you go out to your plants before dawn and soak every one you wish to save until after sunrise and the dripping plants then freeze, frost will be repelled.
Set up a good oscillating sprinkler. The coldest time of day is just before dawn and the chloroplasts are in cold-induced limbo. Before the sun shines and degenerates the cell, continuously applied water will stave off frost and its damage.
If organic nutrients were applied to these areas, the early morning frost-busting watering would also dissolve them into the soil.
I want to close by reminding everyone that the Peninsula has the best gardening microclimate in America. Don’t let a few frosts rob you of the enjoyment of flowers and produce. And with the arrival of cold days … dew stay well all!
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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 news@peninsuladailynews.com (subject line: Andrew May).
