Perilla

Var. frutescens carries larger, flatter leaves and is grown to seed; var. crispa is smaller, frillier and deeply toothed and is grown as a leaf. They differ in their aromatic substances as well as their form, and a grower chooses between them before anything else, because harvest, spacing and timing follow from that choice and not from the species.

Fertilizer rates, timing, and forms should follow local soil tests and regional guidance. AgricultureID does not publish universal fertilizer recommendations.

Perilla seed oil is dominated by alpha-linolenic acid, with much smaller shares of linoleic and oleic acid; the reported ranges are in the key facts. That composition is the reason the crop is grown and also the reason the oil oxidises quickly, so pressing, packaging and storage practice matter more than they do for a stable oil.

Soil suitability should be assessed with local soil survey information and, where available, field testing.

Leaf perilla is cut repeatedly from the same plants and marketed fresh, so it behaves like a cut herb rather than a seed crop: it is grown close, harvested often, and its quality is a matter of leaf size, colour and aroma rather than yield per hectare.

Perilla leaf is widely sold as "sesame leaf" in Korean markets and groceries. It is a mint, not a sesame, and sesame leaves are not the same product. Anyone matching this crop against a trade record or a recipe has to resolve that name before the record means anything.

Perilla is short-day and flowers as daylength shortens in late summer, which suits the seed crop and works against the leaf crop, because flowering ends useful leaf production. Leaf growers in protected culture extend the day with supplementary light for exactly this reason.

As a Lamiaceae, perilla shares pests and diseases with basil and mint rather than with the oilseed rotation, and downy mildew of basil is a relevant concern where the two are grown together. It gives no rotational break from other mint-family crops.

Management combines resistant varieties, rotation, monitoring, and — where justified — locally authorized control products applied according to their labels.

Perilla has naturalised widely outside cultivation, including in parts of North America, where it is regarded as a pasture weed and is documented as toxic to cattle when consumed in quantity at flowering. That the same species is a valued crop and a listed pasture problem is a genuine feature of its status.

The seed is small and the seed oil deteriorates in the seed as well as in the bottle, so seed for pressing is harvested promptly and dried, and seed for planting has short viability compared with cereal seed. Planting old perilla seed is a common cause of poor stands.

Korea grows perilla at national scale for oil and leaf, Japan grows both types with a strong culinary leaf tradition, and China grows it for seed. Outside East Asia it is a specialty crop, so most production knowledge is in those countries' extension systems.