Repotting guide

When & how to repot Peacock fern (Selaginella uncinata)

Also called peacock spikemoss, blue spikemoss, rainbow moss, spring blue spikemoss.

More about peacock fern

About Peacock fern

Selaginella uncinata · also called peacock spikemoss, blue spikemoss · houseplant

Peacock fern is a low, creeping spikemoss from southern China grown for its iridescent blue-green foliage — not a true fern. It demands constant moisture, high humidity and shade, so it thrives in terrariums. ASPCA lists its close relative Selaginella kraussiana as non-toxic, so it is treated as pet-safe; confirm with your vet.

Mature size: Around 8-15 cm (3-6 in) tall, spreading 30-45 cm (12-18 in) wide

How to tell peacock fern needs repotting

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

Roots creeping out of the drainage holes or matting tightly across the soil surface.
The rootball dries out within a day or two no matter how much you water.
Water channels straight down the gap between rootball and pot without wetting the centre.
Steady decline — thin growth, persistent crispy edges — that good humidity and watering have not fixed. Only then is the disturbance of a repot worth the risk for peacock fern.

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 peacock fern

Every 1–2 years, disturbing the roots as little as possible. Peacock fern's growth habit — low, dense, fast-spreading evergreen groundcover with creeping horizontal stems — sets the pace. Peacock fern is a low, creeping spikemoss from southern China grown for its iridescent blue-green foliage — not a true fern. It demands constant moisture, high humidity and shade, so it thrives in terrariums. ASPCA lists its close relative Selaginella kraussiana as non-toxic, so it is treated as pet-safe; confirm with your vet.

What size pot to step peacock fern up to

Go up only one size and handle the rootball as little as possible. Peacock fern resents root disturbance, so the goal is to slide the intact rootball into slightly more soil — not to tease, wash or prune the roots. A modest step up means less shock and a faster recovery.

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 peacock fern

Early spring, just as new growth restarts, is the ideal window for peacock fern. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting peacock fern

Keep disturbance to a minimum. Peacock fern resents root disturbance, so the plan is to move the intact rootball — not to wash, tease or prune the roots.
Choose just one size up. Pick a pot only one size larger with drainage, and have moisture-retentive moisture-retentive, mineral-rich, well-drained mix ready.
Slide the rootball out whole. Water the day before, then ease peacock fern out keeping the rootball intact. Gently free only the roots that are circling the very bottom.
Nestle it into fresh soil. Add a base layer of fresh mix, set the rootball in at the same depth, and backfill gently around the sides without packing hard.
Water and protect. Water in, then keep it warm, humid and out of direct sun for a few weeks while it re-roots. Expect a short sulk — that is normal.

Aftercare

Expect peacock fern to sulk for a couple of weeks — that is normal after any root disturbance for this group. Keep it warm, humid and out of direct sun, water just enough to keep the mix lightly moist, and do not panic and overwater while it re-roots. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for peacock fern

Peacock fern wants moisture-retentive, mineral-rich, well-drained mix. Use a humus-rich, mainly mineral medium that holds moisture but still drains — for example peat-free compost or coir blended with perlite and a little fine bark. It tolerates acid, neutral or alkaline pH but will not survive soils that dry hard. A shallow pot or terrarium substrate suits its creeping, surface-rooting habit. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting peacock fern — frequently asked questions

How often should you repot peacock fern?

Every 1–2 years, disturbing the roots as little as possible for peacock fern. Repot peacock fern every 1–2 years, disturbing the roots as little as possible — it sulks for weeks if the rootball is teased apart. Slide it into one size up in spring with fresh moisture-retentive, mineral-rich, well-drained mix, keep it warm and humid afterwards, and never bare-root or hard-prune the roots.

What size pot does peacock fern need?

When is the best time of year to repot peacock fern?

Why does peacock fern sulk after repotting?

Peacock fern resents root disturbance, so a wilt or stall for a week or two after repotting is normal, not a failure. Minimise it by keeping the rootball intact, stepping up just one size, and keeping the plant warm, humid and out of direct sun while it re-roots.

Should you fertilise peacock fern after repotting?

Not immediately. Wait about 4 weeks after repotting peacock fern. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.