Pteris Care Guide

Pteris, commonly known as brake fern, is one of the more forgiving ferns you can grow in a UK home. It handles lower light than many of the ferns we grow and is happy in the cooler corners where some tropical houseplants struggle. It is also pet-safe, making it a practical choice for homes with curious cats and dogs.

In this guide, we’ll cover everything you need to know about growing Pteris, including light, watering, soil, repotting, humidity and propagation, as well as the cultivars worth looking out for and the common problems we see in customer queries and at the nursery.

Light Requirements

Pteris is happiest in bright, indirect light, but it is also one of the more tolerant ferns when it comes to lower light. An east- or north-facing window can provide ideal conditions, while variegated cultivars tend to hold their colour best when kept away from direct sunlight. At the nursery, we grow ours under shade cloth to protect the delicate fronds from stronger light.

Too much direct light can cause the fronds to bleach to a pale yellow-green, while variegated forms may gradually lose some of their contrast. Older fronds can also develop crispy edges as they become stressed. On the other hand, very low light can result in long, thin new growth with weaker stems, and variegated plants may slowly produce greener leaves.

One of the great things about Pteris is that it can cope with the less-than-perfect light found in many UK homes. A dim hallway, north-facing room or bathroom with frosted glass can all work well, provided the plant is still getting enough natural light to grow. If your home is short on bright windows, Pteris is certainly a fern worth considering.

How Often to Water Pteris

Water Pteris as soon as the top centimetre of compost feels dry to the touch. The exact frequency will vary depending on the temperature, light levels and time of year, but in a typical centrally heated UK home, you may find yourself watering around twice a week during spring and summer and roughly once a week during winter. The important thing is not to stick rigidly to a schedule, but to check the compost regularly and never allow it to dry out completely.

When watering, give the plant a thorough drink until water begins to run from the drainage holes in the bottom of the pot. Allow the excess to drain away fully before returning the plant to its usual spot. Bottom watering can also work particularly well for ferns. Place the nursery pot in a saucer or bowl of tepid water for around 20 minutes, allowing the compost to draw up the moisture it needs, then lift the pot out and let any remaining water drain away. Keeping the crown and foliage above the water also helps avoid leaving the centre of the plant unnecessarily wet.

Getting the balance right is important. If Pteris is overwatered, the fronds may start to yellow from the base outwards and the compost can develop a sour smell. Persistently wet conditions can also cause the roots to turn brown and mushy. This is usually a sign that the compost is staying saturated for too long rather than simply that the plant has been watered.

Underwatering tends to show itself more quickly. The tips and edges of the fronds will turn crispy and brown, and if the plant remains dry for several days, entire fronds can collapse. Unfortunately, once a Pteris frond has completely crisped, it will not recover. Remove damaged fronds at the base and concentrate on keeping the remaining compost consistently moist so that new growth has the conditions it needs.

Tap water is fine for a brake fern. They are less sensitive to mineral build-up than calathea or maidenhair ferns. If you live in a hard water area and notice white salt deposits at the soil surface, flush the pot through with rainwater or filtered water every couple of months.

Soil and Potting Mix

Pteris want a moisture-retentive but free-draining mix. A standard houseplant compost holds too much water and a cactus mix dries out too fast. We use our Simply Houseplant Tropical Potting Mix at the nursery, which holds moisture without compacting, and that is what we recommend at home.

For a self-mixed blend, two parts Jungle Mix to one part fine bark and a handful of worm castings gives a rich, even-moisture mix that suits brake ferns well.

Avoid heavy peat-based composts that compact down over time. Ferns hate sitting in airless, soggy compost as much as they hate going dry.

Repotting

Repot every 18 to 24 months, in spring. Pteris develop a dense rhizome at the surface, and you will see fronds starting to push out over the rim of the pot when it is time. Choose a pot only one size up; brake ferns dislike a lot of unused compost around the rhizome.

Tease away any compacted compost, prune any dead or papery rhizome with clean scissors, and settle the plant into fresh mix at the same depth it was growing before. The rhizome should sit just at the surface, never buried. Water in well and keep slightly shaded for two weeks while new roots establish.

Humidity and Temperature

Pteris appreciates higher humidity, with around 50% or above being ideal. That said, it is more forgiving than many tropical ferns and can cope with the 40–50% humidity found in many UK homes. You may notice it grows more happily in rooms where the air is naturally more humid, such as bathrooms and kitchens.

If the air in your home is particularly dry, there are several simple ways to increase the humidity around your plant. Grouping Pteris with other houseplants can create a slightly more humid microclimate, while placing the pot near a pebble tray can add a little moisture to the surrounding air. A small humidifier is another option if you are looking to maintain a more consistent level of humidity, particularly during winter when central heating can dry the air considerably.

We do not recommend relying on misting as a way to increase humidity. Any increase in ambient humidity is very short-lived, while regularly leaving the fronds wet can encourage bacterial or fungal spotting, particularly where there is limited airflow.

In terms of temperature, Pteris is comfortable between around 12 and 22°C. It is one of the more cold-tolerant houseplant ferns, so it can happily sit in a slightly cooler hallway or porch during winter. Try to avoid sudden changes in temperature and cold draughts, however, and keep the plant away from radiators and other direct heat sources, which can dry the fronds out quickly.

Feeding

Feed every two to three weeks in spring and summer with a balanced houseplant feed at half the strength on the bottle. Ferns are not heavy feeders and a full-strength dose will burn the delicate frond tips. Stop feeding from mid-October until late February.

Propagation

Pteris propagate by rhizome division, not by node cuttings. The method we use at the nursery:

1. In spring, tip the plant out of its pot. You will see a creeping woody rhizome with multiple fronds emerging along it.
2. Slice through the rhizome cleanly with a sharp knife, leaving at least three or four fronds and a healthy section of roots on each division.
3. Pot each division into fresh compost in a small pot, water in well, and keep in a shaded, humid spot for three to four weeks while new roots establish.

Pteris will also self-seed from spores in a humid greenhouse or terrarium environment, but this is slow and the variegated cultivars do not come true from spore. Stick to division at home.

Common Problems when growing Pteris as a Houseplant

Crispy brown frond tips is almost always underwatering, sometimes paired with low humidity. Trim the damaged tips back to clean tissue and water more attentively. Once a frond has crisped, that frond will not recover.

Yellowing fronds from the base can be overwatering, especially in winter. Check the compost is not waterlogged and let the top centimetre dry slightly between waterings.

Pale or washed-out variegation might mean too much direct sun on a variegated cultivar. Move it back from the window or into an east-facing spot.

Whole plant collapsing is usually root rot from waterlogged compost. Tip the plant out, cut back to healthy white roots, repot into fresh mix and water sparingly until it stabilises.

Small brown dots in lines on the underside of fronds are spores, not pest damage. Healthy ferns produce spores when mature; you can ignore them or use a soft brush to clear them off if you prefer the look.

Cottony tufts at the base of fronds indigate mealybug. Spot treat with surgical spirit on a cotton bud, then follow up with diluted insecticidal soap. Our full mealybug guide has the protocol we use at the nursery.

If you are unsure whether a frond is on the way out or recoverable, send us a clear photo and we are happy to take a look.