Background: This study was done in the light of concept safety production of medicinal and aromatic plants.
Materials and Methods: This study was conducted in open fields for two seasons continuously to compare the effects of organic
fertilizer, soil amendments, a mixture of them and chemical NPK fertilizer (control) on growth parameters, floral characteristics and
chemical constituents of Oenothera biennis L. (evening primrose) plants. Results: The outcome data pointed out that mixture of organic
fertilizers (cattle manure and humic substances) and soil amendments (zeolite and magnetite) led to significant increment in
morphological growth (plant height, number of branches, number of leaves, leaves area, leaves fresh weight and leaves dry weight), floral
characteristics (number of flower, number of capsules, seed yield as well as health index) and chemical composition symbolized in plant
pigments, total carbohydrates, net photosynthesis, stomatal conductance, water use efficiency, crude protein, total phenolics, N, P, K%,
moreover indigenous hormones characterized in Indole Acetic Acid (IAA), gibberellic acid (GA3), cytokinins (CK) and abscisic acid (ABA),
fixed oil content in seeds and oil yield per hectare in comparison with the recommended dose of chemical fertilizer NPK (control) under
the same conditions. From an economic view, the feasibility study of experiment clearly indicated that mix of organic and natural fertilizers
proven its value and potential to achieve maximum profitable returns. Conclusion: These results disclose that mixture organic and natural
resources of fertilizers could reduce or replace the addition of chemical fertilizers, accordingly improve the quality and quantity of
medicinal and aromatic plants, besides minimizing economic costs and pollution of the agricultural environment.