North Carolina gardeners have a reasonably long gardening season of approximately 180 days between frosts. Still, any gardener worthy of the name is always looking for a way to hasten that first bite of green or to postpone the final day of harvest. Tools do exist and not only can they accelerate and extend the harvest, they can actually improve harvest yields and quality. Cloches, row covers, cold frames, plastic tunnels, and variations of these are all in the gardener’s bag of tricks for season extending.

Cold frames and cloches have a long and honored place in gardening tradition. Cold frames are bottomless boxes, usually made of wood, which have glazing of some sort which admits sunlight (traditionally, a discarded but unbroken storm window) for a top. They are used as a halfway house for seedlings, allowing them to harden up to outside conditions after a cozy indoor beginning without having to face the extremes of the open garden. They can also be used to produce crops in either early spring or late fall, and even on into winter. Lettuce, radishes, small cabbage varieties, or other cool weather crops will thrive well into winter in the cool but protected environment of the cold frame. A steep top angle will allow the greatest amount of light and heat into the frame during the winter when the sun is low in the sky. Continue to monitor the temperature of the frame when using it for winter crop or a sunny day might result in prematurely cooked vegetables.

The original cloche was a glass bell jar popular in the market gardens of Paris. Today’s cloche may be anything from a waxed paper tent to a bottomless plastic milk jug, but they all help protect young plants from early frosts and drying winds. Some of the newer tools include solar collectors such as water filled tubes to provide additional frost protection.

Floating row covers are great season extender. Several brands of lightweight spun-bonded fabrics are available to drape over rows and even over entire gardens. As the plants grow, they lift the fabric. While they give some frost protection (about four degrees), they are most valuable for letting plants get the most out of the early spring sun by providing protection from drying winds and by boosting daytime temperatures under the cover. These fabrics provide excellent protection from flying insect pests; imagine a wormless broccoli harvest without applying a drop of pesticide. Harvests of warm weather vegetables should be earlier when plants are started under a row cover. Remember that the cover will need to be removed to allow insect pollination as necessary. At the end of the season, the row covers make convenient blankets to toss over plants when frost is predicted.

There are many variations of these devices available for purchase or for the making. The novice gardener may want to experiment with a few simple cloches or a row cover in order to lengthen the gardening season by a few weeks at each end. The experienced gardener may be able to extend the gardening season to 365 days a year.

To learn more about Season Extension, visit the NC Extension Growing Small Farms website: https://growingsmallfarms.ces.ncsu.edu/growingsmallfarms-seasonextension/ and the NCSU Extension Gardener Handbook: https://content.ces.ncsu.edu/extension-gardener-handbook/appendix-e-season-extenders-and-greenhouses.

N.C. Cooperative Extension provides information to help people, businesses and communities solve problems, develop skills and build a better future. Extension specializes in agriculture, 4-H youth development, communities, food and nutrition, and the environment. To learn more about our programs, please visit: https://union.ces.ncsu.edu/.