Optimum Harvesting Time of Four Mentha Species in Northern Finland

Abstract

The effect of harvesting time on the quality and quantity of mint oils produced from plants grown in short summer and long-day climatic conditions of northern Finland (64°40′N and 25°E) was examined to determine what growth stage is best for cutting to obtain the highest possible biomass (herb yield), oil content and suitable oil composition. In the field experiment, plants cut only once at the end of August were compared with those of two cuttings. The first cut was at the beginning of August and the second cut in the middle of September. The mint species were Mentha piperita L. “peppermint”, M. canadensis “cornmint”, M. canadensis “Sakhalin mint” and M. spicata L. “spearmint.”