Repotting guide
When & how to repot Green Shiso (Perilla frutescens var. frutescens)
Also called Green Shiso, Ao Shiso, Green Perilla.
More about green shiso
About Green Shiso
Perilla frutescens var. frutescens · also called Green Shiso, Ao Shiso · herb
Green shiso is a fragrant mint-family annual prized in Japanese cooking for its bright green, frilly, basil-and-anise-scented leaves used with sashimi and tempura. It grows fast in warm conditions, prefers moist, fertile soil and gentle afternoon shade in hot regions, and self-seeds readily. Pinch flower spikes to keep leaves tender and prolong harvest.
Mature size: 45-90 cm tall and 30-45 cm wide.
How to tell green shiso needs repotting
Repotting on a calendar is less reliable than reading the plant. For green shiso, 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 green shiso 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 green shiso
Pot on seedlings as they grow; not a perennial repot. Green Shisois grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Upright, branching aromatic annual with square stems and large, broad, serrated, frilly green leaves; produces slender flower spikes of tiny white flowers in late summer..
What size pot to step green shiso up to
Pot green shiso 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 green shiso
Pot green shiso 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 green shiso
- Pot on before it is root-bound. Check green shiso 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 fertile, moisture-retentive loam 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 green shiso 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 green shiso
Green Shiso wants fertile, moisture-retentive loam. Rich, humus-rich, well-drained soil, pH 5.5-6.5. Incorporate compost before planting; lean, dry soils give small, hard, less flavourful leaves. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.
Repotting green shiso — frequently asked questions
How often should you repot green shiso?
Pot on seedlings as they grow; not a perennial repot for green shiso. Green Shiso is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into fertile, moisture-retentive loam 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 green shiso need?
Pot green shiso 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. Use our pot size calculator to size it from the plant's current pot and root spread.
When is the best time of year to repot green shiso?
Pot green shiso 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.
Can you put green shiso straight into a much bigger pot?
No. Even a fast-growing green shiso 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 green shiso after repotting?
Not immediately. Wait about 1 week after repotting green shiso. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.
Related guides
- Green Shiso care — light, water, soil and common problems
- How often to water green shiso — the watering brief
- How to repot a plant — the complete step-by-step method
- Root-bound plant — how to spot and fix it
- Pot size calculator — size the next pot correctly
- When & how to repot basil
- When & how to repot herb garden
- When & how to repot mint
- All 5561 repotting guides in the Growli library