Fertilising guide
How to fertilise Queen of the Night (Selenicereus grandiflorus)— schedule & NPK
Also called Large-Flowered Cactus, Sweet-Scented Cactus, Night-Blooming Cereus.
More about queen of the night
About Queen of the Night
Selenicereus grandiflorus · also called Large-Flowered Cactus, Sweet-Scented Cactus · flowering
Selenicereus grandiflorus is a sprawling, vining cactus from the Caribbean and Mexico, famous for producing the largest and most intensely fragrant cactus flowers in the world — up to 30 cm wide — which open for a single night only. A dramatic flowering specimen for a bright, warm room. Needs support as it sprawls extensively. Generally pet-safe as a true cactus.
Growth habit: Sprawling, vining, epiphytic cactus with aerial roots
What fertiliser queen of the night actually wants — and why
Queen of the Night 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 queen of the night: 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 queen of the night, 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 queen of the night:
Feed every two weeks from spring through late summer with a balanced liquid fertiliser at half-strength, switching to a high-potassium feed (e.g. tomato fertiliser) in midsummer to encourage flower bud formation. 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 queen of the night 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 queen of the night
Half strength is the safe default for queen of the night — 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 queen of the night first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the queen of the night watering schedule.
Signs you are over-feeding queen of the night
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for queen of the night:
- 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 queen of the night
- 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 queen of the night care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of queen of the night 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 queen of the night
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 queen of the night — frequently asked questions
What fertiliser does queen of the night 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. Queen of the Night 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 queen of the night?
Feed every two weeks from spring through late summer with a balanced liquid fertiliser at half-strength, switching to a high-potassium feed (e.g. tomato fertiliser) in midsummer to encourage flower bud formation. Feed every two weeks from spring through late summer with a balanced liquid fertiliser at half-strength, switching to a high-potassium feed (e.g. tomato fertiliser) in midsummer to encourage flower bud formation. 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 queen of the night?
Half strength is the safe default for queen of the night — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding queen of the night 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 queen of the night 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 queen of the night?
Flush the pot of queen of the night 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
- Queen of the Night care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water queen of the night — 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 showy stonecrop
- How to fertilise orpine
- How to fertilise flowering currant
- All 11687 fertilising guides in the Growli library