How to grow shiso
Overview
Shiso (Perilla frutescens var. crispa) is a fast-growing annual herb in the mint family, prized for its ruffled leaves and unique cinnamon-cumin flavour. It is grown for continuous leaf harvest and thrives in warm, humid conditions with consistent moisture.
Varieties
- Green Shiso — Classic green-leaved variety with a mild, fresh flavour, ideal for salads and garnishes.
- Red Shiso — Deep purple-red leaves with a stronger, spicier taste; used in pickling and Japanese dishes.
Soil Preparation
Shiso prefers rich, well-drained soil with a pH of 6.0–7.0. Incorporate compost or aged manure before planting to boost organic matter. Ensure good drainage to prevent root rot.
Growing Guide
Sow shiso seed directly into well-drained soil at 3mm depth, spacing 30cm apart. Germination takes 7–14 days in warm soil (20–25°C). For best leaf production, plant in full sun with rich, moist soil and pinch out flower buds as they appear. In cooler zones, start indoors or use cloches to extend the season.
Sowing
Sow shiso seed 3mm deep in warm soil after the last frost. Space 30cm apart; germination takes 7–14 days at 20–25°C. Direct sow is best, but transplanting is fine if started early.
Care
Feed shiso with a balanced liquid fertiliser every 2–3 weeks during active growth. Pinch out the topmost shoots regularly to encourage bushy, leafy growth and delay flowering. Remove any flower spikes as they appear to extend the harvest period.
Companion Planting
Shiso grows well alongside ginger and radishes, which share similar moisture and warmth needs. Avoid planting near fennel or strong-scented herbs that may compete for space.
Common Pests & Risks
Watch for cutworms at the base of young plants; use collars or diatomaceous earth. Aphids and whitefly may appear on new growth; spray with neem oil or a strong water jet.
Harvesting
Harvest shiso leaves when they are fully expanded and unblemished, typically 6–8 weeks after sowing. Pick regularly from the top to encourage bushier growth; delay harvest if flowering begins to maintain leaf quality.
In the Kitchen
Use shiso leaves fresh in salads, wraps, or as a garnish for sushi and noodles. They can be chopped into stir-fries or pickled in vinegar for a tangy condiment. Store in a damp paper towel in the fridge for up to a week.
Troubleshooting
Yellow leaves: often caused by overwatering or poor drainage; reduce watering and improve soil. Brown leaf edges: usually from underwatering or low humidity; increase moisture and mist leaves. Stunted growth: may be due to cold soil or frost; wait for warm weather or use cloches. Leaf drop: common after flowering; pinch off buds to extend harvest. Leggy plants: lack of sun; move to full sun or prune back.