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Fertilising guide

How to fertilise Table Fern (Pteris vittata)— schedule & NPK

Also called Table Fern, Ladder Brake Fern, Arsenic Fern.

More about table fern

About Table Fern

Pteris vittata · also called Table Fern, Ladder Brake Fern · houseplant

Pteris vittata is a fast, finely cut brake fern with ladder-like fronds of narrow pinnae on wiry stems. It is famous as a hyperaccumulator that pulls arsenic from soil. Indoors it makes an easy, airy tabletop fern, tolerating more light and slightly drier spells than most ferns while still wanting steady moisture and humidity.

Growth habit: Clump-forming terrestrial fern with arching, once-pinnate fronds rising from a short rhizome; spreads readily by spores.

What fertiliser table fern actually wants — and why

Table Fern is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.

A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula.

For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for table fern: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.

How often to feed table fern, and which months

Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For table fern:

Feed every 4-6 weeks in spring and summer with a balanced liquid feed diluted to half strength. Ferns are salt-sensitive, so dilute well and flush the pot occasionally. Stop feeding in winter. Treat that as every 4-6 weeks between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.

The dormant-season rule matters more than the exact interval: skip feeding entirely when table fern is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.

What strength to mix for table fern

Half strength is the safe default for table fern — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

Feeding always goes onto already-damp soil, never dry roots — water table fern first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the table fern watering schedule.

Signs you are over-feeding table fern

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for table fern:

Signs you are under-feeding table fern

If the symptoms point at watering, light or roots rather than nutrition, the full table fern care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush the pot of table fern with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.

Organic vs synthetic feeds for table fern

Organic options

A diluted seaweed or worm-casting feed, or fish emulsion if you can tolerate the smell indoors. UK: Westland or Baby Bio Organic, dilute seaweed; US: Espoma Indoor! or Neptune's Harvest fish & seaweed. Slow, gentle and hard to overdo.

Synthetic / liquid feeds

A general-purpose houseplant liquid at half strength — UK: Baby Bio, Westland Houseplant Feed or Phostrogen; US: Miracle-Gro Indoor Plant Food or Schultz. Convenient and fast-acting; the only risk is overdoing it.

Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.

Fertilising table fern — frequently asked questions

What fertiliser does table fern need?

A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula. Table Fern is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.

How often should I feed table fern?

Feed every 4-6 weeks in spring and summer with a balanced liquid feed diluted to half strength. Ferns are salt-sensitive, so dilute well and flush the pot occasionally. Stop feeding in winter. Feed every 4-6 weeks in spring and summer with a balanced liquid feed diluted to half strength. Ferns are salt-sensitive, so dilute well and flush the pot occasionally. Stop feeding in winter. Treat that as every 4-6 weeks between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.

What strength of feed for table fern?

Half strength is the safe default for table fern — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

What does over-feeding table fern look like?

Brown, crispy leaf tips and edges with no sign of underwatering. A white, crusty salt deposit on the soil surface or pot rim. Weak, pale, stretched new growth that flops. Lower leaves yellow and drop while the soil is correctly watered. Feeding table fern year-round on a fixed schedule, including dark winter months, is the most common mistake — it cannot use the nutrients in low light and the surplus simply burns the roots and crusts the soil.

Should I flush the soil of table fern?

Flush the pot of table fern with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.

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