Seasonal variation in essential oil yield and composition from Thymus vulgaris L. during different growth stages in the south of Jordan

The effect of plant space and time of harvesting on yield and quality of Thymus vulgaris was evaluated in Jordan. Thyme was cultivated in rows of 50 cm apart with inter-row spacing of 15, 30 or 45 cm and was grown at various development stages. Plants were harvested during different growth stages including vegetation, beginning of blooming, full blooming and fruit maturation. Results indicated that oil yields of thyme were affected by growth stage and inter-row spacing. The maximum oil yields was obtained by harvesting at the early growth stage, which was found superior to oil yield corresponding to the later stages of collection. With 45 cm inter-row spacing, the maximum oil yield was recorded when the samples were collected at growth stage. Indicated results showed that the chemical composition during various growth stages was characterised by high percentage of carvacrol and its corresponding monoterpenic hydrocarbon precursors rho-cymene and gamma-terpinene, and ether 1,4-cineol.