Yarb Tales - Save the Potted Plants
October 31, 2016

The Heritage Herb Garden at the Ozark Folk Center graces the park with colors, textures and sweet and pungent aromas. With their natural display, the herbs help us to interpret the history of the human use of plants.

Eventually we gardeners are going to have to decide whether or not to save our potted plants from freezes this winter. Here at the Ozark Folk Center we are blessed with structures made for this purpose, the greenhouse and cold frames. Decisions about which plants are moved to the warmth of the greenhouse, nestled into cold frames or sent to the compost pile are based on value, available space and the health of the individual plant. Some plants are very tender, some are semi-hardy and some are very hardy but are planted in clay or cement pots that will break if filled with frozen potting medium.

Hardy perennials in plastic pots are protected in unheated cold frames. The roots are not as hardy as the tops of these plants so the pots have to be sunk in sand, bark or wheat straw mulch. Our cold frames are made with arches of bent PVC pipe and protected from freezing winds with a covering of UV treated plastic. The ends of the cold frame hoops are left open for good air circulation unless the temperatures get down in to the low 20s. Our native plant collection, as well as thyme, winter savory, sage, hibiscus, roses and hardy flowering perennials spend the winter in the cold frame because they do better if they are allowed to go dormant. Insect pests are not as active on plants left in the cold so we can concentrate pest control activities on those in the warmer environment of the greenhouse.

Tender perennials such as sweet marjoram and Mexican mint marigold are placed in the heated cold frame. This unit has a floor of sand with a heat cable buried about two inches below the surface. The thermostat is set at 50° F and, with the plastic covering, the environment inside feels just like spring all winter. Plant roots are kept at a constant warm temperature while the tops are somewhat cooler; depending upon how cold it is outside. This keeps insect pest damage at a minimum. All we have to do is keep the cold frames watered and open and close the ends of the hoop framing.

Inside the greenhouse is where the fun work happens. Daytime temperatures can get into the 80s and 90s on a sunny day. Pests don’t go dormant and must be controlled with a scouting and spraying schedule. Dead and dying leaves are cleaned up on a daily basis. Right now we are giving each plant a good pruning, spraying and a new pot before it takes its place on the bench. Puttering in the greenhouse is one of our favorite activities! Regardless of the weather outside, the greenhouse is warm and bright inside. Winter is a time to relate to greenhouse plants as individuals. Healthy, vigorous plants start from healthy, vigorous parent plants. Seedlings and cuttings are propagated on heat mats and under mist. Next season’s garden plants begin their lives in the greenhouse.

We will be growing and grooming the plants for our gardens and market for the next three months! If you wish you could play in a greenhouse, call (870) 269-3851 and let us know when you can come! We appreciate willing hands and will answer questions as we work. If I don’t see you in the future, I’ll see you in the pasture!