Fertilising guide
How to fertilise Silver lace fern (Pteris ensiformis 'Evergemiensis')— schedule & NPK
Also called silver lace fern, silver brake fern, slender brake fern, Victorian table fern, sword brake fern.
More about silver lace fern
About Silver lace fern
Pteris ensiformis 'Evergemiensis' · also called silver lace fern, silver brake fern · houseplant
Silver lace fern is a compact tropical brake fern prized for fronds striped with silvery-white centres. Indoors it wants bright indirect light, constantly moist humus-rich soil, and high humidity, and it has zero tolerance for drying out. The ASPCA lists Pteris ferns as non-toxic to cats and dogs, making it a pet-safe choice.
Growth habit: Compact, clump-forming evergreen fern with upright-to-arching finely divided fronds; slow to moderate grower
What fertiliser silver lace fern actually wants — and why
Silver lace 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 silver lace 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 silver lace 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 silver lace fern:
Feed monthly through spring and summer with a balanced liquid houseplant feed diluted to half strength; ferns are light feeders and full-strength fertiliser can burn the roots and brown the frond tips. Stop feeding in autumn and winter. Treat that as monthly 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 silver lace 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 silver lace fern
Half strength is the safe default for silver lace 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 silver lace fern first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the silver lace fern watering schedule.
Signs you are over-feeding silver lace fern
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for silver lace fern:
- 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.
Signs you are under-feeding silver lace fern
- Uniformly pale or yellow-green leaves, oldest first.
- Noticeably small new leaves and stalled growth in good light and season.
- A generally tired, lacklustre look despite correct watering and light.
If the symptoms point at watering, light or roots rather than nutrition, the full silver lace fern care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of silver lace 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 silver lace 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 silver lace fern — frequently asked questions
What fertiliser does silver lace 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. Silver lace 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 silver lace fern?
Feed monthly through spring and summer with a balanced liquid houseplant feed diluted to half strength; ferns are light feeders and full-strength fertiliser can burn the roots and brown the frond tips. Stop feeding in autumn and winter. Feed monthly through spring and summer with a balanced liquid houseplant feed diluted to half strength; ferns are light feeders and full-strength fertiliser can burn the roots and brown the frond tips. Stop feeding in autumn and winter. Treat that as monthly 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 silver lace fern?
Half strength is the safe default for silver lace fern — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding silver lace 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 silver lace 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 silver lace fern?
Flush the pot of silver lace 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.
Keep reading
- Silver lace fern care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water silver lace fern — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise snake plant
- How to fertilise dracaena
- How to fertilise peperomia
- All 569 fertilising guides in the Growli library