In order to evaluate the possibilities of cultivation of Khorasan thyme (Thymus transcaspicus), an experiment was conducted in the years 2006 and 2007 under field conditions at the Research Station of the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. Irrigation intervals (2, 3 and 4 weeks as main plot) and cattel manure (10, 20 and 30 t ha-1 as subplot) were employed within a split-plot design with three replications. Plant biomass and its components as proportion of leaf, stem and flowers and also essential oil percentage and yield were measured at final harvest. Phenological cycles were recorded during the two years of the experiment. Results indicated that increasing application of organic manure beyond 10 t ha-1 did not show any significant effect on plant biomass. Increasing irrigation intervals in the second year of trial, significantly (p < 0.05) reduced plant biomass. This was also true for stem, leaf and flower content in dry matter. Essential oil content and yield in response to organic manure and irrigation showed no particular trend. Phenological cycles were completed in 192 days equivalent to 3300 degree-days in the first year and 172 days equivalent to 3050 degree-days in the second year. The constituents of essential oil under field conditions were 25 components, which were 43.1% of the total essential content with thymol as the main constituent.

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