Predicting frost.

Behold the turtle. He makes progress only when he sticks his neck out.
~James Bryant Conant

I have been hardening off my plants, not because the weather has stabilized (because it hasn't), but because they have grown too big to squeeze them all under the Grow Lights in my basement. I was hoping that my large south-facing living room window would suffice, but the plants were getting leggy for stretching for even more sunlight. So now they are braving the elements, and for the most part, I feel like a proud mama whose babies are "all growed up". At first I was worried about frost, but then I learned a few tricks on how to predict it.

Frost involves chance and risk. It's reputation is a bit scary as we have all heard horror stories of frost damage claiming the lives of young seedlings and prized plants. Frost punishes the ill-prepared or forgetful, but it can be tamed with knowledge, foresight and planning.

You can determine the likelihood of frost scientifically if you know the dew point, the temperature and expected low. The National Gardening Association's KidsGardening.com states, "If the air temperature is below the dew point and below freezing, frost occurs." Say the current temperature is 56˚F, and the dew point is 42˚F, if the temperature fell to 44˚F, no frost; if it fell to 38˚F, still no frost. If it fell to 31˚F, frost would occur. To find current temperatures, dew points, and expected lows, Weather.com's Gardener's Local Forecast is a great resource for this data, or watching the local weather report on your late night news, like KDKA or WTAE in Pittsburgh, PA.

Through observation, you can also predict a frost. Say the sky is clear, but the temperatures fall steadily throughout the day, there is a chance of frost. But if it's cloudy or rainy, chances are a frost will not occur because the clouds and moisture will act as a blanket. To learn more about these observational methods, read Eliot Tozer's article on Predicting Frost on OrganicGardening.com and Marion Owen's article on How to Predict a Frost on Plantea.com.

If there is a chance of frost, protect your plants from possible damage by moving them indoors or protecting them under garden cloches, hoophouses, greenhouses, Reemay cloth, tents, tarps, shower curtains, plastic sheets, 5-gallon buckets, plastic grocery bags, trash bags, pillowcases, bedsheets or anything that will keep frost away from the plant. Make sure that the covering is properly secured and supported so that it does not weigh down on or damage the plant stems and foliage.