Repotting guide

When & how to repot Fairy Thimbles (Campanula cochleariifolia)

Also called Fairy thimbles, Fairies' thimbles, Spiral bellflower.

More about fairy thimbles

About Fairy Thimbles

Campanula cochleariifolia · also called Fairy thimbles, Fairies' thimbles · flowering

Campanula cochleariifolia is a low-growing, rhizomatous alpine perennial from the mountain ranges of Europe, where it spreads through crevices and scree by slender underground runners. It produces a carpet of rounded, bright-green leaves topped with nodding, thimble-sized, pale-blue or white bells from midsummer into autumn. It is one of the most easily grown alpine bellflowers and tolerates light foot traffic between paving stones, but it will not tolerate waterlogged soil in winter. Campanula species are considered non-toxic to cats and dogs by the ASPCA.

Mature size: 5–10 cm tall; spreads 30–60 cm or more where happy.

Watch for — Rust and powdery mildew: Can affect plants in humid, poorly ventilated spots; ensure good air circulation and remove affected leaves promptly.

How to tell fairy thimbles needs repotting

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

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

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 fairy thimbles

Every 2–3 years, into bone-dry mix. Fairy Thimbles's growth habit — mat-forming, rhizomatous perennial spreading by slender underground stolons, forming a low carpet of foliage. — sets the pace. Campanula cochleariifolia is a low-growing, rhizomatous alpine perennial from the mountain ranges of Europe, where it spreads through crevices and scree by slender underground runners. It produces a carpet of rounded, bright-green leaves topped with nodding, thimble-sized, pale-blue or white bells from midsummer into autumn. It is one of the most easily grown alpine bellflowers and tolerates light foot traffic between paving stones, but it will not tolerate waterlogged soil in winter. Campanula species are considered non-toxic to cats and dogs by the ASPCA.

What size pot to step fairy thimbles up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Fairy Thimbles stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

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 fairy thimbles

Spring or summer, while fairy thimbles is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting fairy thimbles

Repot dry. Do not water fairy thimbles for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty moist but well-drained; chalk, loam, or sand ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set fairy thimbles at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep fairy thimbles completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for fairy thimbles

Fairy Thimbles wants moist but well-drained; chalk, loam, or sand. Thrives in gritty, fertile, slightly alkaline to neutral soil; avoid clay or compacted soils that hold excessive moisture. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting fairy thimbles — frequently asked questions

How often should you repot fairy thimbles?

Every 2–3 years, into bone-dry mix for fairy thimbles. Repot fairy thimbles every 2–3 years into a snug pot of moist but well-drained; chalk, loam, or sand, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does fairy thimbles need?

When is the best time of year to repot fairy thimbles?

Should you water fairy thimbles after repotting?

No — not straight away. Repot fairy thimbles into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise fairy thimbles after repotting?

Not immediately. Wait about 3 weeks after repotting fairy thimbles. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.