Yarb Tales:

The Heritage Herb Garden at the Ozark Folk Center graces the park with visual colors and textures, sweet and pungent aromas and helps us to interpret the history of the human use of plants.

There is much more growing on our herbs than what meets the eye. Being familiar with the plant parts that we cannot see are very important to successful cultivation. As our herb garden team plants seeds, cuttings and root divisions in pots and in the garden, we are constantly taking action to enhance healthy root growth. These actions include transplanting potted plants when they show signs of being root bound; making sure that our herbs have good drainage; using potting mixtures that contain friendly fungus and mycorrhizia and feeding the plants and their growing media with natural fertilizers.

We know potted plants are suffering when the leaves begin to yellow or turn black. We notice and take action when water flows straight through the root ball and is not absorbed. We turn such a plant out of its pot and find that the roots are crowded and are in the shape of the pot; they are often brown or turning dark and have few white roots. Sometimes, roots may have grown out of the pot through the drainage hole. At this point, either the specimen must be root pruned and given fresh growing medium or planted out into the garden or the plant will die. If the roots are given room and fresh medium, new roots will grow and the plant will usually recover.

Roots are covered with tiny hairs, which take in water and minerals from the growing medium. This solution moves upward through the stems from the roots to the leaves. Food produced by photosynthesis in the leaves moves down through the vascular system to the roots.

Microorganisms living on and around the plant roots, together with the roots, create a zone called the rhizosphere.  (This term, rhizosphere, was coined by a scientist named Hiltner in 1904.)  Russian studies have shown that roots not only take up water and nutrients, but also excrete CO2 and other acids into the rhizosphere. These excretions feed and nurture beneficial microbes which, in turn, digest and make the minerals soluble in the growing medium. Phosphorus, which is not water soluble, is made available through the action of carbonic and nitric acids that are present in the zone.

One of the best organisms in the rhizosphere to help plants resist disease is called mycorrhizal fungi. These fungi live in partnership with plant roots. As mycorrhizae multiply, they extend hyphae (the growing tips) into the surrounding soil. As they travel, these hyphae contact soil nutrients and exude acids and enzymes that make the nutrients soluble so that plants can take them up. Plant roots are surrounded in a protective sheath of mycorrhizae that both encourage friendly organisms and discourage the growth of plant pathogens. This has been shown in field trials.

The best way to encourage mycorrhizal fungi is to make and use compost. Incorporate compost into the soil when planting, apply it on the soil surface under existing plants and spray compost tea on leaves. Compost tea helps to suppress foliar plant diseases.

Compost tea can be made in many ways. This is but one recipe. Use a five-gallon plastic bucket with two gallons of water added. If you are using city water, stir and allow time for the chlorine to escape (at least overnight or 24 hours is best). Use an old sock or stocking for a tea bag. To the sock, add three cups of compost and one cup of alfalfa meal (available at the feed store). Tie off the top of the sock. Add about a 1/2 of sorghum syrup or molasses to the water. Stir to dissolve. Sink the sock in the water. Stir the tea twice a day, without fail or install an aquarium bubbler. Brew for three days. Filter the tea through old tee-shirt material or other loose-weave cloth before filling your sprayer. Spray plants before sunrise or just after sunset; never foliar spray when the sun is shining. Alternatively, dilute the tea, using about a gallon to four gallons of water when watering.

We have received excellent weather this spring. With the warm days and generous rainfall all of our garden friends are accelerating their top growth. Keep your plants healthy for the rest of the summer by attending to the plant parts that are not seen. Healthy roots are a product of healthy soil; together these components produce healthy plants. If I don’t see you in the future—I’ll see you in the pasture!