EFFECT OF HARVEST TIME ON THE LEMON BALM ESSENTIAL OILS

The effects of cutting and harvest time on the essential oil content of lemon balm Melissa officinalis L. were studied in 2007 and 2008. The oil content varied greatly, in the range of 0.12 to 0.25% (0.048 to 0.1 g plant^-1), in the first and second cuttings. The oil yield was particularly high at 5 pm (0.25% or 0.1 g per plant), in the first cutting. Harvest at 5 pm resulted in the highest percentages of main components (citronellal, citronellol and geranyl acetate) of the essential oil extracted. The highest percentage of monoterpene compounds was observed at 5 pm, whereas the content of sesquiterpene compounds culminated at 1 pm.