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Standardization of media and nutrient concentration for coleus (Plectranthus barbatus Andr.) under substrate culture

Sharma, Y., Vasundhara, M.
Journal of plant nutrition 2018 v.41 no.4 pp. 445-452
Nematoda, Plectranthus barbatus, cost benefit analysis, culture media, fertilizers, forskolin, medicinal plants, nitrogen, nutrient content, nutrient solutions, nutrients, peat, phosphorus, potassium, roots, sand, soil, soil-borne diseases, vermiculite
Coleus (Plectranthus barbatus Andr.) is a medicinal herb whose roots contain forskolin. Incidences of soil-borne diseases, wilt complex and nematodes are the major limiting factors for growing this crop under soil media. Hence, an investigation was initiated for the standardization of soilless growth media and nutrient solution concentration in coleus. Coco peat, vermiculite, sand and their combinations were used as potting media with different concentrations of nutrients based on the recommended dose of fertilizers for soil media (1,080 mg plant⁻¹ nitrogen, 960 mg plant⁻¹ phosphorous and 1200 mg plant⁻¹ potassium). Among the different media and nutrients, plants grown under coco peat media with 80% of the recommended dose of fertilizer for soil (864 mg plant⁻¹ nitrogen, 768 mg plant⁻¹ phosphorous and 960 mg plant⁻¹ potassium) recorded significantly higher root yield (17.10 tha⁻¹) and quality parameters (0.98% forskolin). Benefit–cost ratio was also recorded maximum (4.25) in the same treatment.