Changes in the essential oil content and composition of palmarosa (Cymbopogon martini) harvested at different stages and short intervals in two different seasons

• Harvesting palmarosa herb between 70 and 80 days produced good quality essential oil.
• In the essential oil geraniol content increased and geranylacetate decreased with age.

The essential oil of palmarosa (Cymbopogon martini Roxb. Wats.), is one of the industrially important essential oils. Since the content and composition of essential oils is known to depend on extrinsic and intrinsic factors, including climate and season of harvest, knowledge of the optimal harvesting time is necessary for production of quality essential oil. Hence, experiments were conducted to study the variation in the essential oil composition of palmarosa harvested twelve times at short intervals during a six month period from October 2012 to March 2013. Chemical profiling of the essential oils was attempted by GC/GC–MS analysis, which revealed the presence of eleven compounds in the essential oil. The compounds are myrcene, cis-β-ocimene, trans-β-ocimene, linalool, neral, geraniol, geranial, geranylacetate, caryophyllene, geranyl isobuterate, and farnesol. A significant increase in the geraniol content and a significant decrease in the geranylacetate were noticed with passage of time.Maximum and minimum temperatures exhibited significant positive correlation with geraniol and showed significant negative relation with geranylacetate. Geraniol and geranylacetate in the essential oil were inversely related.Ideal harvesting time is around 70–80 days taking in to consideration of oil content, oil yield/plant and the content of geraniol and geranylacetate in the essential oil.