Yield Potential of Selected Medicinal Herbs Grown at Three Plant Spacings in New Mexico

Abstract

Field studies were conducted to determine the production potential of echinacea (Echinacea purpurea), valerian (Valeriana officinalis), mullein (Verbascum thapsus) and yerba mansa (Anemopsis californica) medicinal herbs at two sites in New Mexico. Las Cruces, N.M., is at an elevation of 3,891 ft (1,186 m) and has an average of 220 frost free days per year, whereas Alcalde, N.M., is at an elevation of 5,719 ft (1,743 m) and averages 152 frost-free days per year. In-row plant spacings of 12, 18 and 24 inches (30.5, 45.7, and 61.0 cm) were compared at both locations. The corresponding plant densities for the 12, 18 and 24 inch spacings were 14,520 plants/acre (35,878 plants/ha), 9,680 plants/acre (23,919 plants/ha), and 7,260 plants/acre (17,939 plants/ha), respectively. Data were collected on growth rates, fresh yield, and dry yield for the herbs grown at each site. All crops at both sites had highest plot yields at the 12-inch spacing, suggesting that optimum in-row plant spacings are at or below the 12-inch spacing. Yields of 1.94 ton/acre (4.349 t·ha-1) of dried yerba mansa root, 0.99 ton/acre (2.219 t·ha-1) of dried echinacea root, and 2.30 ton/acre (5.156 t·ha-1) of dried mullein leaves were realized at the 12-inch spacing at Las Cruces in southern New Mexico. Yields of 1.16 ton/acre (2.600 t·ha-1) of dried valerian root, 0.93 ton/acre (2.085 t·ha-1) of dried echinacea root, and 0.51 ton/acre (1.143 t·ha-1) of dried mullein leaves were harvested at the 12-inch spacing at Alcalde in northern New Mexico. Yields of fresh echinacea flowers were 1.56 ton/acre (3.497 t·ha-1) in Las Cruces. Yields of dried mullein flowers were 0.68 ton/acre (1.524 t·ha-1) in Las Cruces and 0.66 ton/acre (1.479 t·ha-1) in Alcalde.