Keep track of frosts' ebb, flow.

Byline: Paul Rogers 

COLUMN: ROOTS OF WISDOM

Gardeners would do well to keep a weather eye on the thermometer these days - and nights. A frosty night can happen almost anytime now that Labor Day is in the rearview mirror.

In the past, farmers believed that the full moon of September, the Harvest Moon, often shone on frosty ground. Weather records list Oct. 17, 172 days after the last of the spring frosts, as the end of the growing season. The 17th of October carries us to within four days of the Hunters Moon. Can we expect the first killing frost to tarry until then?

With due recognition to regional weather records, homeowners discover that the records of greatest value to them are the dates that they personally record. There are numerous geographic and environmental factors that modify local weather. Are you positioned on a slope? Cold air drains downhill, just like water. It is not unusual to discover crops damaged by frost at the lower end of the row, while the crops uphill experience no harm.

Do you live near a body of water? Ponds, lakes, and reservoirs serve as heat sinks. The water holds warmth and releases it overnight. Cities and towns radiate considerable quantities of heat from roads, walks, buildings and other hard surfaces. It is not unusual to not record a damaging frost within a city until a month after the countryside has been chilled.

Even on a single homestead, there can be considerable differences in effects from the first couple of frosts. Called "microclimates," these are areas by stone outcroppings, against concrete walls and alcoves facing south. An observant homeowner soon identifies these areas. They are where the cat sleeps on sunny autumn days, where the first dandelions flower in the spring, and where the snow first melts.

These areas are used equally well in the spring as well as the autumn as gardening "season-extenders." By planting the earliest of the spring flowering bulbs and perennials in these microclimates, the spring season can be advanced by one to three weeks. By a judicial use of sheets and blankets, with stakes to protect the plants from the weight of the covers, a three- to four-week extension of the fall growing season can be achieved.

Yet, it is fall. The calendar says so. The autumnal equinox arrives in four days. The nightly drop in temperature and resultant moisture film on cars reinforces what we already know. The shift in tree leaves from green to autumnal colors reminds all that the seasons "they are a-changin.'" The wise gardener will not wait until a frosty night sends him out into the dark garden to salvage what he is able. Keep up the harvest on a daily basis. Know which crops will be destroyed by frost and what vegetables will not notice the cold. Tomatoes, peppers and eggplants must be picked or pulled. Root crops such as carrots, turnips, beets, radishes and parsnips can remain until much later. Pumpkins, squash, and cucumbers will have their vines frosted, and the fruit may be damaged.

If the harvesting is being conducted comfortably during the daylight, rather than frantically by lantern or flashlight, do not forget to pick armloads of flowers that can also be in danger of a black death by white frost. Most of the blooms of garden perennials will not suffer from the frost, but tender perennials such as dahlias will be destroyed. Pick the flowers. Assemble bouquets. Bring them to work and share them with friends. Celebrate the change - it is happening!