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Repotting guide

When & how to repot Mint (Mentha)

Also called peppermint, spearmint, garden mint.

About Mint

Mentha · also called peppermint, spearmint · herb

Mint is a vigorous spreading perennial herb that thrives in damp soil and partial shade. Best grown in a sunken pot or dedicated bed to stop it taking over. Easy and forgiving. Toxic to pets in large quantities — keep out of reach of cats and dogs.

Mint (Mentha species, Lamiaceae) is a perennial aromatic herb of temperate Eurasia and naturalised worldwide; in the wild it favours damp ground along streams and ditches, which explains its preference for consistently moist soil.

It is notoriously invasive, spreading by horizontal rhizomes that travel several feet a year and surface as new plants well away from the parent; the standard recommendation is to confine it to a deep (12-18 in) pot or a sunken root barrier rather than open ground.

Mature size: 30-60 cm tall, spreading

Watch for — Spreading everywhere: Rhizomes — grow in a sunken pot or dedicated bed.

Sources: en.wikipedia.org, almanac.com

How to tell mint needs repotting

Repotting on a calendar is less reliable than reading the plant. For mint, 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 mint

Pot on seedlings as they grow; not a perennial repot. Mintis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Spreading rhizomatous perennial herb.

What size pot to step mint up to

Pot mint 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 mint

Pot mint 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 mint

  1. Pot on before it is root-bound. Check mint 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 rich, moisture-retentive 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 mint 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 mint

Mint wants rich, moisture-retentive loam. Tolerates a wide range. Container culture prevents the rhizomes from invading the rest of the garden. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting mint — frequently asked questions

How often should you repot mint?

Pot on seedlings as they grow; not a perennial repot for mint. Mint is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into rich, 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 mint need?

Pot mint 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 mint?

Pot mint 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 mint straight into a much bigger pot?

No. Even a fast-growing mint 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 mint after repotting?

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

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