Stevia (Stevia rebaudiana) is a small, herbaceous plant in the sunflower family (Asteraceae). It is a perennial in its native South America, but is grown as an annual in all but the warmest areas of the United States. Stevia is commonly called “sweetleaf” or “sugarleaf” because it contains a glycoside in its leaves that imparts a sugary taste. Ground-up stevia leaves, as well as crude leaf extracts, have been used as a natural sweetener all over the world.
Growing stevia for bedding plant production is likely the most viable market for Kentucky growers interested in this crop. Greenhouse herb and bedding plant growers could consider adding stevia to their production line. One herb supplier advertises plug trays of stevia that can be ready for resale as 4-inch potted plants in about eight weeks. Food ingredient manufacturers are refining stevia for use in foods, but that stevia is sourced from South American and Asian growers, especially China. It is extremely difficult for new, untested growers to break into this market. Large-scale growers who have demonstrated success in growing stevia may eventually be able to secure a contract with domestic or foreign buyers. There were no stevia processing plants in the U.S. as of September 2016, according to North Carolina State University; a company purchasing stevia from North Carolina growers ships dried stevia out of the country for processing.
GREENHOUSE-GROWN TRANSPLANTS - Stevia transplants can be produced under similar greenhouse conditions as common flower and vegetable transplants. Plants can be produced in multi-pack containers or in individual 4- or 6-inch containers. Plants can be produced from seed or cuttings, and small greenhouse producers should consider purchasing plugs from wholesale plug specialists for finishing in larger containers. Vegetatively produced propagules from reliable sources are preferred to ensure production of plants with consistent sugar (glucoside) profiles. FIELD-GROWN - Stevia prefers well-drained soil rich in organic matter. Do not plant in field sites subject to flooding or puddling, or in saline soils. While plants are somewhat drought-tolerant, a consistent source of moisture should be supplied via trickle irrigation. Most sources recommend frequent, shallow irrigations because stevia’s feeder roots tend to be produced near the soil surface. Research in Ontario has shown that stevia has low nutrient requirements, and excess nitrogen can result in profuse plant growth with poor flavor.