Zheng, Y., Dixon, M. and Saxena, P. 2006. Greenhouse production of Echinacea purpurea (L.) and E. angustifolia using different growing media, NO 3 -/NH 4 + ratios and watering regimes. Can. J. Plant Sci. 86: 809-815. Current field cultivation and wild-harvest methods for the medicinal plant Echinacea are struggling to meet the requirements for a high-quality, uniformly produced crop for human consumption. To help meet this challenge, the potential of using a greenhouse production system for Echinacea production was explored. Echinacea purpurea (L.) Moench and angustifolia DC. var. angustifolia plants were grown in three types of greenhouse production systems: (1) deep flow solution culture (D), (2) pots with either Pro-Mix (P) or (3) sand (S). Plants were irrigated with one of three nutrient solutions containing NO 3 -/NH 4 + ratios of 7:1, 5:1 or 3:1, respectively. The plants grown in the Pro-Mix and the sand systems were either well-watered or subjected to periodical water stress. The results obtained after 12 wk of growth showed that Echinacea root production in the greenhouse systems was comparable with or better than that in the field. Based on root and total biomass production, the Pro-Mix system was the best production system for both E. angustifolia and E. purpurea. In most cases, the NO 3 -/NH 4 + ratio did not have significant effects on the growth of either species. When effects were seen, however, higher NO 3 -/NH 4 + levels generally resulted in greater leaf area, root and total biomass, and a higher root/shoot ratio. Mild periodic water stress did not affect the root/shoot ratio or the root biomass in either species. The application of a periodic water stress reduced leaf area of both species, but a reduction in total biomass was only observed in E. purpurea. angustifolia DC var. angustifolia en serre selon trois systèmes de production : 1) culture hydroponique profonde (D), 2) en pots dans le mélange Pro-Mix (P) ou 3) dans du sable (S). Les plants ont été arrosés avec une de trois solutions nutritives contenant un rapport de NO 3 -/NH 4 + de 7:1, 5:1 ou 3:1, respectivement. Les plants poussant dans le mélange Pro-Mix et le sable ont été soit copieusement arrosés, soit périodiquement soumis à un stress hydrique. Au bout de 12 semaines, les résultats indiquent que la production de racines par les plants d'Echinacea cultivés en serre est comparable ou supérieure à celle des plants cultivés en pleine terre. Compte tenu de la biomasse des racines et de la biomasse totale, le système utilisant le mélange Pro-Mix s'avère le meilleur pour les deux espèces testées. Dans la plupart des cas, le ratio NO 3 -/NH 4 + n'a pas d'incidence significative sur la croissance. Quand on observe des effets cependant, on remarque généralement qu'un rapport NO 3 -/NH 4 + plus élevé entraîne une augmentation de la surface foliaire, de la biomasse des racines et de la biomasse totale ainsi que du rapport racines/pousses. Un stress hydrique périodique modéré ne modifie le ratio racines/pousses ni la biomasse des racines chez ...