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Fertilising guide

How to fertilise Common Butterwort (Pinguicula vulgaris)— schedule & NPK

Also called Bog violet.

More about common butterwort

About Common Butterwort

Pinguicula vulgaris · also called Bog violet · flowering

Pinguicula vulgaris is a cold-hardy temperate butterwort of wet, alkaline-to-neutral fens and bogs across northern Europe, Asia, and North America. Its flat rosette of yellow-green, sticky leaves traps tiny insects and it bears solitary violet flowers in spring. It forms a winter resting bud and requires a genuine cold dormancy and permanently wet ground.

Growth habit: Flat rosette of broad, upturned-edged yellow-green sticky leaves; produces single violet flowers on tall stalks, then dies back to a tight winter hibernaculum that often makes resting gemmae.

What fertiliser common butterwort actually wants — and why

Common Butterwort 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 common butterwort: 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 common butterwort, 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 common butterwort:

Do not fertilise the roots. It captures small flying insects on its sticky leaves; outdoors it needs no help. Mineral feed harms it. 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 common butterwort 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 common butterwort

Half strength is the safe default for common butterwort — 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 common butterwort first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the common butterwort watering schedule.

Signs you are over-feeding common butterwort

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

Signs you are under-feeding common butterwort

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

Flushing and leaching the salts

Flush the pot of common butterwort 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 common butterwort

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 common butterwort — frequently asked questions

What fertiliser does common butterwort 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. Common Butterwort 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 common butterwort?

Do not fertilise the roots. It captures small flying insects on its sticky leaves; outdoors it needs no help. Mineral feed harms it. Do not fertilise the roots. It captures small flying insects on its sticky leaves; outdoors it needs no help. Mineral feed harms it. 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 common butterwort?

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

What does over-feeding common butterwort 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 common butterwort 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 common butterwort?

Flush the pot of common butterwort 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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