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Repotting guide

When & how to repot Courgette (Cucurbita pepo 'Defender')

Also called courgette, zucchini, summer squash.

More about courgette

About Courgette

Cucurbita pepo 'Defender' · also called courgette, zucchini · edible

Courgette, or zucchini, is a fast, prolific bush summer squash cropping heavily from midsummer to first frost. It is a hungry, thirsty, tender annual needing full sun, very rich moist soil and warmth. Keep picking fruits young to sustain production; a couple of healthy plants can overwhelm a household with fruit through the season.

Mature size: 60-90 cm tall and wide; fruits picked young at 10-20 cm long

How to tell courgette needs repotting

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

Pot on seedlings as they grow; not a perennial repot. Courgetteis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Vigorous, frost-tender annual; most modern cultivars are open bush types with large lobed leaves and short internodes, producing fruit continuously at the plant's centre rather than running like a trailing squash..

What size pot to step courgette up to

Pot courgette 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 courgette

Pot courgette 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 courgette

  1. Pot on before it is root-bound. Check courgette 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 very rich, moisture-retentive, free-draining soil, ph 6.0-7.0 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 courgette 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 courgette

Courgette wants very rich, moisture-retentive, free-draining soil, ph 6.0-7.0. Wants deep, fertile soil loaded with organic matter to feed heavy fruiting and hold moisture. Plant on or beside a compost-enriched mound or planting pocket; good drainage prevents the stem and root rots this crop is prone to. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting courgette — frequently asked questions

How often should you repot courgette?

Pot on seedlings as they grow; not a perennial repot for courgette. Courgette is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into very rich, moisture-retentive, free-draining soil, ph 6.0-7.0 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 courgette need?

Pot courgette 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 courgette?

Pot courgette 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 courgette straight into a much bigger pot?

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

Not immediately. Wait about 1 week after repotting courgette. 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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