The study with sage (Salvia officinalis L.) cv. ‘Bona’ was conducted in the years 1997–1999. The effect of time of harvest on yield of fresh herb sage and yield of air dry herb, yield of air dry leaves sage. The experiment was conducted with sage two-year old. Sage transplants were planted in distance 30×40 cm. The plant material was harvested twice – in May and in September. Harvest date hat significant influence on the weight of fresh sage herb. Yield of fresh sage herb in September was bigger (190.2 dt ha^-1) than yield of fresh sage herb in May (104.7 dt ha^-1). The percentage quantity of the essential oil in the herb and leaves of sage was depended on the harvest date. The herb and leaves of sage in September had bigger the percentage quantity of the essential oil than in May. The percentage quantity of the essential oil in the leaves of sage, witch was collected in September amounted above 1.5%.

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