Fertilising guide
How to fertilise Moss Campion (Silene acaulis)— schedule & NPK
Also called Moss Campion, Cushion Pink, Moss Pink.
More about moss campion
About Moss Campion
Silene acaulis · also called Moss Campion, Cushion Pink · flowering
Moss Campion is an iconic arctic-alpine cushion plant forming dense, bright-green hummocks studded with tiny pink to magenta flowers in early summer. Native to high mountains and arctic tundra across the Northern Hemisphere, it is one of the slowest-growing alpine plants. Perfect for alpine troughs; demands sharp drainage, cool roots, and full sun.
Growth habit: Extremely compact, cushion-forming perennial; one of the most dense cushion alpines; very slow growing
What fertiliser moss campion actually wants — and why
Moss Campion 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 moss campion: 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 moss campion, 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 moss campion:
No feeding needed; rich soils are harmful. At most, top-dress with a thin layer of grit and a few granite or limestone chips annually to maintain drainage around the cushion collar. Any fertiliser application risks destroying the compact habit. Treat that as sparingly through the growing season 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 moss campion 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 moss campion
Half strength is the safe default for moss campion — 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 moss campion first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the moss campion watering schedule.
Signs you are over-feeding moss campion
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for moss campion:
- 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 moss campion
- 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 moss campion care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of moss campion 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 moss campion
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 moss campion — frequently asked questions
What fertiliser does moss campion 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. Moss Campion 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 moss campion?
No feeding needed; rich soils are harmful. At most, top-dress with a thin layer of grit and a few granite or limestone chips annually to maintain drainage around the cushion collar. Any fertiliser application risks destroying the compact habit. No feeding needed; rich soils are harmful. At most, top-dress with a thin layer of grit and a few granite or limestone chips annually to maintain drainage around the cushion collar. Any fertiliser application risks destroying the compact habit. Treat that as sparingly through the growing season 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 moss campion?
Half strength is the safe default for moss campion — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding moss campion 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 moss campion 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 moss campion?
Flush the pot of moss campion 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
- Moss Campion care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water moss campion — 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 dianthus gratianopolitanus 'firewitch'
- How to fertilise dianthus 'mrs sinkins'
- How to fertilise phlox paniculata 'starfire'
- All 8452 fertilising guides in the Growli library