Fertilising guide

How to fertilise Peace lily (Spathiphyllum wallisii)— schedule & NPK

Also called spathiphyllum, closet plant, white sails.

About Peace lily

Spathiphyllum wallisii · also called spathiphyllum, closet plant · flowering

Peace lily is a shade-loving tropical aroid that wilts theatrically the moment it is thirsty and bounces back within an hour of a soak. Its white "flowers" are modified leaves called spathes. Tolerant of low light, fussy about tap water, mildly toxic to pets.

Spathiphyllum is native to the humid understorey of tropical American rainforests (notably central and southern Mexico, with related species through tropical America and Malesia), growing in shaded, consistently moist forest floors near streams.

Apply a balanced liquid fertiliser roughly monthly during active growth; wiping the leaves clean of dust improves photosynthesis and overall vigour.

Growth habit: Clumping rosette evergreen

Sources: rhs.org.uk, aspca.org, en.wikipedia.org

What fertiliser peace lily actually wants — and why

Peace lily 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 peace 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 peace 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 peace lily:

Balanced liquid feed at quarter strength every 4-6 weeks during the growing season; over-feeding burns leaf tips. The pattern that matters: feed little and often through active growth and budding — every 4-6 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 peace 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 peace lily

Very dilute — quarter strength, the classic "weakly, weekly" approach for peace lily. 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 peace lily first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the peace lily watering schedule.

Signs you are over-feeding peace lily

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

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 peace lily

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 peace lily 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 peace lily 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 peace lily

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 peace lily — frequently asked questions

What fertiliser does peace lily 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. Peace lily 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 peace lily?

Balanced liquid feed at quarter strength every 4-6 weeks during the growing season; over-feeding burns leaf tips. Balanced liquid feed at quarter strength every 4-6 weeks during the growing season; over-feeding burns leaf tips. The pattern that matters: feed little and often through active growth and budding — every 4-6 weeks — and ease right off during the rest period that triggers the next flush.

What strength of feed for peace lily?

What does over-feeding peace lily 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 peace lily 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 peace lily?