Repotting guide

When & how to repot Shiso (Perilla) (Perilla frutescens)

Also called Shiso, Perilla, Beefsteak plant, Perilla mint, Japanese basil, Purple mint.

More about shiso (perilla)

About Shiso (Perilla)

Perilla frutescens · also called Shiso, Perilla · herb

Shiso (Perilla frutescens) is a fast-growing, mint-family culinary annual prized in Japanese, Korean and Vietnamese cooking for its fragrant green or purple leaves. Give it warm weather, full sun to light shade and steady moisture. It is not ASPCA-listed but contains perilla ketone, so treat it as mildly toxic and keep curious pets away.

Mature size: About 30-90 cm (1-3 ft) tall and 30-45 cm (12-18 in) wide

Watch for — Powdery mildew and fungal leaf spot: Humid, crowded or poorly drained conditions cause white powdery coating or dark spots on leaves. Improve airflow, space plants 20-30 cm apart, water at the soil line, and avoid overhead watering.

How to tell shiso (perilla) needs repotting

Repotting on a calendar is less reliable than reading the plant. For shiso (perilla), watch for these signs:

Roots circling the bottom of the module or pot, or poking out of the drainage holes.
The seedling dries out within a day and growth has visibly stalled.
Roots are white and matted in a tight spiral when you tip the plant out.
It has outgrown its current container for the stage of the season — pot shiso (perilla) on before it becomes hard root-bound.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot shiso (perilla)

Pot on seedlings as they grow; not a perennial repot. Shiso (Perilla)is grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Fast-growing, upright, bushy warm-season annual herb in the mint family (Lamiaceae) with square stems and aromatic, serrated, ovate green or purple leaves. Pinch the tips regularly from about 15 cm (6 in) tall to encourage branching and delay flowering..

What size pot to step shiso (perilla) up to

Pot shiso (perilla) on gradually — a seedling jumped straight into a huge pot sits in cold, wet, airless soil and stalls. Step up one or two sizes at a time as the roots fill each container, finishing in a large final pot or the ground. The aim is roots that never circle and never check.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot shiso (perilla)

Pot shiso (perilla) on through the active growing season, whenever roots fill the current container — there is no single date, just "before it becomes root-bound". Avoid potting on during a cold snap.

Step-by-step: repotting shiso (perilla)

Pot on before it is root-bound. Check shiso (perilla) regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
Step up one or two sizes. Choose the next container up — not a giant one. Cold, wet, unused soil around a small root system stalls seedlings.
Knock it out gently. Support the stem, tip the pot, and ease the rootball out without breaking it. A little teasing of circled roots at the base is fine.
Pot into rich mix. Set it into fresh rich, fertile, well-draining loam with high organic matter at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
Water in and grow on. Water well, keep it in good light, and resume feeding once it is established and growing again.

Aftercare

Water shiso (perilla) in well and keep it in bright light; a freshly potted-on seedling can wilt for a day while roots settle, so do not overcompensate by drowning it. Do not fertilise for about 1 week — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for shiso (perilla)

Shiso (Perilla) wants rich, fertile, well-draining loam with high organic matter. Thrives in medium to rich, moisture-retentive soil amended with compost; tolerates sandy soils and a wide pH range around neutral (about 6.0-7.0). Good drainage is essential. For pots, use a quality all-purpose potting mix in a container at least 15 cm (6 in) deep and wide. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting shiso (perilla) — frequently asked questions

How often should you repot shiso (perilla)?

Pot on seedlings as they grow; not a perennial repot for shiso (perilla). Shiso (Perilla) is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into rich, fertile, well-draining loam with high organic matter so the roots never circle the cell, ending in a large final container. A root-bound transplant stalls and never fully recovers.

What size pot does shiso (perilla) need?

When is the best time of year to repot shiso (perilla)?

Can you put shiso (perilla) straight into a much bigger pot?

No. Even a fast-growing shiso (perilla) should only go up one pot size at a time. A vastly oversized pot holds a reservoir of wet soil the roots cannot reach, which stays cold and soggy and rots the roots — the opposite of what you wanted.

Should you fertilise shiso (perilla) after repotting?

Not immediately. Wait about 1 week after repotting shiso (perilla). Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.