Button fern (Pellaea rotundifolia) care

Ferns · needs attention to keep

Last updated 26 October 2026

Button fern (Pellaea rotundifolia) wants medium to bright indirect light. Water it every 6 days. Let the top of the compost dry slightly between waterings. Unusually for a fern, button fern rots if it is kept constantly wet. Pot it in moisture-retentive peat-free compost with perlite. A weak balanced feed monthly in spring and summer, and repot once a year. Humidity: moderate; it copes with drier air than most ferns. The ASPCA lists it as non-toxic to cats and dogs.

The button fern: low, arching fronds of small, round, dark-green leaflets like buttons on a string. It comes from New Zealand and, unusually for a fern, wants to dry slightly between waterings — it rots if kept wet.

Quick facts

Water: Water every 6 days. Let the top of the compost dry slightly between waterings. Unusually for a fern, button fern rots if it is kept constantly wet.
Light: Medium to bright indirect light.
Humidity: Moderate; it copes with drier air than most ferns.
Soil: Moisture-retentive peat-free compost with perlite.
Feeding: A weak balanced feed monthly in spring and summer.
Repotting: Repot once a year.
Toxic to pets: Non-toxic to cats and dogs. The ASPCA lists Cliff Brake (Pellaea rotundifolia) as non-toxic to cats and dogs (checked 26 October 2026).
Difficulty: Needs attention.
Mature size: 15–30 cm tall.
Native to: New Zealand.

Watering a Button fern

Water every 6 days. Let the top of the compost dry slightly between waterings. Unusually for a fern, button fern rots if it is kept constantly wet.

That cadence is the one PlantParlour sets for this species when you name it, and it is deliberately on the cautious side — a plant that asks a day early is safer than one that asks a day late. Log each watering and the reminder moves with the plant rather than with the calendar.

Light

Medium indirect light, and never direct sun. A bright north window or a well-lit bathroom is close to ideal.

Humidity and temperature

Moderate; it copes with drier air than most ferns. Central heating in winter is what turns a comfortable room into a dry one, and it is the usual reason an established plant suddenly browns at the edges or picks up spider mites.

Soil and potting

A mix that holds water without turning to mud: compost with perlite and a little bark. Ferns have fine roots that must never dry out completely.

Feeding

A weak balanced feed monthly in spring and summer. Stop feeding in autumn and start again when you see new growth in spring — feeding a plant that isn't growing just builds up salts in the pot.

Repotting

Repot once a year. Every spring. Divide the clump at the same time if it has filled the pot.

Common problems

Fronds yellowing and the crown going soft
Kept too wet.

Fix: Let the top of the compost dry between waterings, in a shallow pot that drains well.

Yellow leaves: how to read it on any plant
Crisp, brown fronds
It dried right out, or sits in hot sun.

Fix: Water before it dries completely, and keep it out of direct sun.

Brown tips and edges: how to read it on any plant
Brown dots in rows under the leaflets
Spores. Completely normal.

Fix: Nothing to do.

Propagation

Divide the clump in spring. Spores work but take the better part of a year.

A cutting taken in PlantParlour keeps its link to the plant it came from, so a propagation years later still traces back to the mother plant — which is the point if you ever sell or trade it.

Toxicity and safety

Non-toxic to cats and dogs.

The ASPCA lists Cliff Brake (Pellaea rotundifolia) as non-toxic to cats and dogs (checked 26 October 2026).

If your pet has eaten a plant, call your vet, the ASPCA Animal Poison Control Center on (888) 426-4435, or the Pet Poison Helpline on (855) 764-7661. Both are open around the clock and may charge a consultation fee. Take the plant or its label with you.

This is general information, not veterinary advice. We don't test plants: what we say about toxicity follows the ASPCA's published plant list as it stood on 26 October 2026, and that list can change. "Non-toxic" means not poisonous — a pet that eats enough of any plant can still vomit, and fertiliser, pesticide or leaf shine on a plant can harm it. It also only helps if the plant is what you think it is. It covers cats and dogs only; ask your vet about rabbits, birds, reptiles or anything else, and a doctor about children. Read our terms.

Every houseplant in the library the ASPCA lists as non-toxic to cats and dogs

Questions people ask

How often should you water a Button fern?

Water every 6 days as a starting point — that is the cadence PlantParlour sets for Pellaea rotundifolia. Let the top of the compost dry slightly between waterings. Unusually for a fern, button fern rots if it is kept constantly wet. Light, pot size and the time of year all move that number, so treat it as a reminder to go and check rather than a rule.

How much light does a Button fern need?

Medium indirect light, and never direct sun. A bright north window or a well-lit bathroom is close to ideal.

Is Button fern toxic to cats and dogs?

Non-toxic to cats and dogs. The ASPCA lists Cliff Brake (Pellaea rotundifolia) as non-toxic to cats and dogs (checked 26 October 2026). If a pet has eaten part of a plant, call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 straight away.

How do you propagate a Button fern?