Growli
Let's go

Repotting guide

When & how to repot Shiso (Perilla frutescens var. crispa)

Also called shiso, perilla, Japanese basil.

More about shiso

About Shiso

Perilla frutescens var. crispa · also called shiso, perilla · herb

Shiso is a fast-growing annual mint relative prized in Japanese, Korean, and Vietnamese cooking for its ruffled green or deep-purple leaves and complex flavour of mint, basil, and anise. It grows easily from seed in warm weather, reaching knee-height in a season, and self-sows readily. Both leaf colours are ornamental as well as edible, thriving in sun to part shade.

Mature size: 45-90 cm tall and 30-45 cm wide

Watch for — Wilting from underwatering: The soft foliage flags dramatically the moment soil dries out. Keep moisture consistent and mulch to buffer the root zone in hot weather.

How to tell shiso needs repotting

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

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

Pot on seedlings as they grow; not a perennial repot. 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, bushy summer annual with square stems and large serrated or ruffled aromatic leaves, producing spikes of tiny flowers in late summer that set abundant self-sowing seed..

What size pot to step shiso up to

Pot 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 shiso

Pot 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 shiso

  1. Pot on before it is root-bound. Check shiso regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
  2. 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.
  3. 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.
  4. Pot into rich mix. Set it into fresh moist, fertile, well-drained loam at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
  5. 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 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

Shiso wants moist, fertile, well-drained loam. Prefers rich, moisture-retentive soil high in organic matter with a pH around 5.5-6.5. Amend with compost before planting; tolerant of a range of soils as long as they stay reasonably moist and drain well. 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 — frequently asked questions

How often should you repot shiso?

Pot on seedlings as they grow; not a perennial repot for shiso. Shiso is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into moist, fertile, well-drained 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 shiso need?

Pot 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 shiso?

Pot 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 shiso straight into a much bigger pot?

No. Even a fast-growing 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 shiso after repotting?

Not immediately. Wait about 1 week after repotting 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