Fertilising guide
How to fertilise Auricula (Primula auricula)— schedule & NPK
Also called Auricula, Bear's ear, Mountain cowslip.
More about auricula
About Auricula
Primula auricula · also called Auricula, Bear's ear · flowering
Primula auricula is an evergreen alpine perennial native to the calcareous mountains of central Europe, from the Alps to the Carpathians, where it grows in rock crevices and limestone cliff faces. In cultivation it is prized for its rounded, fleshy, mealy leaves and richly fragrant, salverform flowers in yellow, purple, red, and cream, appearing in mid-spring. The most important care fact is to protect the rosette from winter wet, which rots the crown — pot-grown auriculas are best moved under glass or into a cold frame from autumn to early spring. This species is toxic to cats, dogs, and horses.
Growth habit: Rosette-forming, clump-building evergreen perennial; may develop a short, upright stem (carrot) with age.
Watch for — Aphids and root aphids: Both foliar and root-feeding aphids attack auriculas; root aphids are particularly difficult to spot — check roots when repotting and treat with a systemic insecticide or drench if colonies are found.
What fertiliser auricula actually wants — and why
Auricula 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 auricula: 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 auricula, 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 auricula:
Feed with a dilute, potassium-rich liquid feed every 2 weeks from bud formation through to late spring; after flowering switch to a balanced feed monthly until late summer. Treat that as every 2 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 auricula 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 auricula
Half strength is the safe default for auricula — 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 auricula first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the auricula watering schedule.
Signs you are over-feeding auricula
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for auricula:
- 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 auricula
- 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 auricula care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of auricula 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 auricula
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 auricula — frequently asked questions
What fertiliser does auricula 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. Auricula 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 auricula?
Feed with a dilute, potassium-rich liquid feed every 2 weeks from bud formation through to late spring; after flowering switch to a balanced feed monthly until late summer. Feed with a dilute, potassium-rich liquid feed every 2 weeks from bud formation through to late spring; after flowering switch to a balanced feed monthly until late summer. Treat that as every 2 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 auricula?
Half strength is the safe default for auricula — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding auricula 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 auricula 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 auricula?
Flush the pot of auricula 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
- Auricula care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water auricula — 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 europeana rose
- How to fertilise sexy rexy rose
- How to fertilise sun flare rose
- All 10153 fertilising guides in the Growli library