Fertilising guide
How to fertilise Calla Lily (Zantedeschia aethiopica)— schedule & NPK
Also called Calla lily, Arum lily, White arum lily, Lily of the Nile, Pig lily, Florist's calla, Trumpet lily.
More about calla lily
About Calla Lily
Zantedeschia aethiopica · also called Calla lily, Arum lily · flowering
The calla lily is a moisture-loving, rhizomatous perennial prized for sculptural white spathes on tall stems. Give it bright indirect light or part shade, consistently damp rich soil, and warmth of 60-80F. Despite the name it is not a true lily but an aroid, and the ASPCA lists it as toxic to dogs and cats.
Growth habit: Clumping, rhizomatous herbaceous perennial forming a basal rosette of arrow-shaped, often glossy leaves, with flowers carried on tall stems above the foliage. Semi-evergreen in mild conditions but deciduous (dies back) in cold or dry spells, returning from the rhizome.
Watch for — Failure to bloom: Usually from too little light, missing the winter dormancy/rest period, or over-feeding with high-nitrogen fertiliser. Provide bright light, a cool dormant rest, and a potassium-rich feed in season.
What fertiliser calla lily actually wants — and why
Calla Lily 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 calla lily: 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 calla lily, 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 calla lily:
Feed monthly with a balanced liquid fertiliser (e.g. 10-10-10) diluted through spring and summer while in active growth. A higher-potassium feed encourages flowering. Stop feeding once the last bloom fades to let the plant enter dormancy, and resume only when new leaves emerge at the soil line. 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 calla lily 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 calla lily
Half strength is the safe default for calla lily — 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 calla lily first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the calla lily watering schedule.
Signs you are over-feeding calla lily
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for calla lily:
- 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 calla lily
- 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 calla lily care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of calla lily 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 calla lily
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 calla lily — frequently asked questions
What fertiliser does calla lily 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. Calla Lily 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 calla lily?
Feed monthly with a balanced liquid fertiliser (e.g. 10-10-10) diluted through spring and summer while in active growth. A higher-potassium feed encourages flowering. Stop feeding once the last bloom fades to let the plant enter dormancy, and resume only when new leaves emerge at the soil line. Feed monthly with a balanced liquid fertiliser (e.g. 10-10-10) diluted through spring and summer while in active growth. A higher-potassium feed encourages flowering. Stop feeding once the last bloom fades to let the plant enter dormancy, and resume only when new leaves emerge at the soil line. 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 calla lily?
Half strength is the safe default for calla lily — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding calla lily 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 calla lily 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 calla lily?
Flush the pot of calla lily 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
- Calla Lily care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water calla lily — 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 peace lily
- How to fertilise bird of paradise
- How to fertilise hoya
- All 609 fertilising guides in the Growli library