Peppermint is grown from roots which can be dug from an existing high quality field, or from greenhouse root cuttings. A variety of disease, insect and weed problems can be brought in with roots from existing fields. While greenhouse starts are free of these problems, they are substantially more expensive. As a result, growers increase a small quantity of greenhouse roots over several years on disease and insect free ground until they have an adequate source of roots. Verticillium wilt is the major disease concern affecting peppermint.
Parasitic nematodes can adversely effect production.
A variety of insects feed on mint in central Oregon. These including spider mites, cutworms, flea beetle, strawberry root weevil, and mint root borer. Adequate weed control is important to both the level of production and oil quality. Peppermint harvest for oil production runs from the first of August through September. Cutting of leaves for tea production is generally made from mid to late July.