Fertilising guide

How to fertilise African violet (Saintpaulia ionantha)— schedule & NPK

Also called Saintpaulia, usambara violet.

About African violet

Saintpaulia ionantha · also called Saintpaulia, usambara violet · flowering

African violet is a compact rosette-forming houseplant from East Africa grown for its near-continuous purple, pink, or white blooms. With consistent warmth, indirect light, and careful watering it flowers year-round. Pet-safe by ASPCA standards.

Saintpaulia ionantha originates from Tanzania, where it grows in the dappled shade and steady warmth of mountain forest, conditions that explain its dislike of direct sun and cold.

Feed regularly but dilutely with a balanced or bloom-formulated African violet fertilizer during growth; steady light feeding sustains its near-continuous flowering under good conditions.

Growth habit: Compact rosette

Sources: missouribotanicalgarden.org, gardens.si.edu

What fertiliser african violet actually wants — and why

African violet is feeding to flower, not to grow leaves — it needs a higher-phosphorus / specialist bloom feed, given little and often, to set and hold its display.

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 african violet: 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 african violet, 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 african violet:

Quarter-strength African violet feed with every watering during the growing season, or a half-strength feed every 2 weeks. The pattern that matters: feed little and often through active growth and budding — every 2 weeks — and ease right off during the rest period that triggers the next flush.

The dormant-season rule matters more than the exact interval: skip feeding entirely when african violet 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 african violet

Very dilute — quarter strength, the classic "weakly, weekly" approach for african violet. These plants have fine roots that scorch easily and a steady trickle beats an occasional strong dose for flowering.

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

Signs you are over-feeding african violet

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

Lush green leaves but few or no flowers (too much nitrogen).
Brown, scorched leaf tips and edges — a classic fine-root burn.
White salt crust on the medium or pot, and stalled buds.
Bud blast: buds forming then shrivelling and dropping.

Signs you are under-feeding african violet

Sparse or no flowering despite good light and the right season.
Smaller, paler new leaves and a generally weak, tired plant.
Flowers that are smaller or fade faster than they should.

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

Flushing and leaching the salts

Specialist and bloom feeds leave salts that scorch fine roots — flush african violet thoroughly with plain water until it runs clear every 4-6 weeks in the feeding season, and always between feeds for orchids.

Organic vs synthetic feeds for african violet

Organic options

Gentler options exist: a dilute seaweed feed (mildly potassium-rich) or worm-casting tea. UK: Westland seaweed, or a dilute tomato feed like Tomorite for bud-formers; US: Espoma Orchid! / Violet! or Neptune's Harvest. Lower burn risk, slower response.

Synthetic / liquid feeds

A species-matched bloom feed at quarter strength — UK: Baby Bio Orchid / African Violet food, or a high-potash Tomorite/Phostrogen for budding bloomers; US: Miracle-Gro Orchid or Bloom Booster, Schultz African Violet.

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 african violet — frequently asked questions

What fertiliser does african violet need?

A higher-phosphorus "bloom" formula or a species-specific feed (orchid food, African violet food, or a tomato-style high-potash/phosphorus liquid). A high-nitrogen general feed gives you lush leaves and almost no flowers. African violet is feeding to flower, not to grow leaves — it needs a higher-phosphorus / specialist bloom feed, given little and often, to set and hold its display.

How often should I feed african violet?

Quarter-strength African violet feed with every watering during the growing season, or a half-strength feed every 2 weeks. Quarter-strength African violet feed with every watering during the growing season, or a half-strength feed every 2 weeks. The pattern that matters: feed little and often through active growth and budding — every 2 weeks — and ease right off during the rest period that triggers the next flush.

What strength of feed for african violet?

What does over-feeding african violet look like?

Lush green leaves but few or no flowers (too much nitrogen). Brown, scorched leaf tips and edges — a classic fine-root burn. White salt crust on the medium or pot, and stalled buds. Bud blast: buds forming then shrivelling and dropping. Using an ordinary high-nitrogen houseplant feed on african violet is the headline mistake — you get a healthy-looking plant that simply refuses to bloom. The second is feeding through the rest period and breaking the dormancy cue it needs to set buds.

Should I flush the soil of african violet?