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Repotting guide

When & how to repot Catnip (Nepeta cataria)

Also called catmint (common), catswort.

About Catnip

Nepeta cataria · also called catmint (common), catswort · herb

Catnip is a hardy mint-family perennial famous for its stimulating effect on cats — about 70% of cats respond to nepetalactone in the leaves. Easy in any sunny well-drained spot. Pet-safe and indeed pet-stimulating; safe in any amount for cats and dogs.

Catnip (Nepeta cataria, Lamiaceae) is a vigorous, somewhat weedy perennial native to Eurasia; its foliage contains nepetalactone, the compound that triggers euphoria in many cats and repels some insects.

Performs well in average, well-drained soil and even thrives in poor soils — overly rich ground produces floppy stems.

Mature size: 60-90 cm tall

Watch for — Cats roll on the plant and crush it: Plant in a wire cloche or grow in a hanging pot until established.

Sources: hort.extension.wisc.edu, plants.ces.ncsu.edu, missouribotanicalgarden.org

How to tell catnip needs repotting

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

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

What size pot to step catnip up to

Pot catnip 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 catnip

Pot catnip 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 catnip

  1. Pot on before it is root-bound. Check catnip 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 free-draining 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 catnip 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 catnip

Catnip wants free-draining loam. pH 6.1-7.8; tolerates poor soils. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting catnip — frequently asked questions

How often should you repot catnip?

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

Pot catnip 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 catnip?

Pot catnip 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 catnip straight into a much bigger pot?

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

Not immediately. Wait about 1 week after repotting catnip. 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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