Fertilising guide
How to fertilise Fishbone Cactus (Epiphyllum anguliger)— schedule & NPK
Also called Zigzag Cactus, Ric Rac Cactus.
More about fishbone cactus
About Fishbone Cactus
Epiphyllum anguliger · also called Zigzag Cactus, Ric Rac Cactus · houseplant
The fishbone cactus is a Mexican epiphyte grown for its deeply zigzagged, flat green stems that trail like a fish skeleton. Easy and forgiving, it thrives in bright indirect light, an airy fast-draining mix, and moderate watering, rewarding a cool dry winter with fragrant night-opening flowers. A spineless jungle cactus and ASPCA-listed non-toxic to pets.
Growth habit: Trailing, freely branching epiphyte of flat, deeply lobed zigzag stems that arch and cascade — ideal for a hanging basket — with fragrant night-blooming flowers appearing on mature plants.
Watch for — Scorched or bleached stems: Excess direct sun pales and burns the flat stems. Move to bright indirect light with only gentle early sun.
What fertiliser fishbone cactus actually wants — and why
Fishbone Cactus is a true minimal feeder — it stores its own reserves and is far more often killed by over-feeding than starved.
A weak, balanced or cactus-formula feed (low, even numbers such as a diluted 5-10-5 or a dedicated cactus food). Nothing high-nitrogen — fast lush growth is exactly what you do not want.
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 fishbone cactus: 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 fishbone cactus, 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 fishbone cactus:
Feed every 2-4 weeks in spring and summer with a balanced or low-nitrogen houseplant feed at half strength; a higher-potash feed ahead of autumn supports blooming. Pause feeding through the cooler winter rest. In practice that is every 2-4 weeks at most, only between spring through early autumn (roughly March to September) — never in the dormant winter months.
The dormant-season rule matters more than the exact interval: skip feeding entirely when fishbone cactus 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 fishbone cactus
Quarter strength is the rule for fishbone cactus. A full-strength dose is a fast route to scorched roots; when unsure, skip a feed entirely rather than double up.
Feeding always goes onto already-damp soil, never dry roots — water fishbone cactus first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the fishbone cactus watering schedule.
Signs you are over-feeding fishbone cactus
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for fishbone cactus:
- A white or yellowish salt crust on the soil surface or pot rim.
- Brown, scorched leaf tips or margins despite normal watering.
- Soft, stretched, floppy growth that flops instead of standing firm.
- Roots that look burnt or brown when you next repot.
Signs you are under-feeding fishbone cactus
- Genuinely rare — these plants coast for a long time on very little.
- Very slow or fully stalled growth across a whole season in good light.
- Overall pale, washed-out colour after years in the same exhausted mix.
If the symptoms point at watering, light or roots rather than nutrition, the full fishbone cactus care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Because you feed so rarely, salts still creep up over time. Flush the pot of fishbone cactus with plain water until it runs freely from the base once or twice a year — and always repot into fresh gritty mix every 2-3 years rather than relying on feed.
Organic vs synthetic feeds for fishbone cactus
Organic options
Worm-casting tea or a very dilute seaweed feed once or twice in the growing season is plenty. In the UK an occasional drop of Westland or Levington seaweed feed; in the US a token quarter-strength Espoma Cactus! liquid. Honestly, fresh gritty mix every couple of years does more than any bottle.
Synthetic / liquid feeds
A purpose-made cactus and succulent feed at quarter strength — UK: Westland or Baby Bio Cacti & Succulent food; US: Miracle-Gro Succulent or Schultz Cactus Plus. Use the cactus formula precisely because it is low-nitrogen.
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 fishbone cactus — frequently asked questions
What fertiliser does fishbone cactus need?
A weak, balanced or cactus-formula feed (low, even numbers such as a diluted 5-10-5 or a dedicated cactus food). Nothing high-nitrogen — fast lush growth is exactly what you do not want. Fishbone Cactus is a true minimal feeder — it stores its own reserves and is far more often killed by over-feeding than starved.
How often should I feed fishbone cactus?
Feed every 2-4 weeks in spring and summer with a balanced or low-nitrogen houseplant feed at half strength; a higher-potash feed ahead of autumn supports blooming. Pause feeding through the cooler winter rest. Feed every 2-4 weeks in spring and summer with a balanced or low-nitrogen houseplant feed at half strength; a higher-potash feed ahead of autumn supports blooming. Pause feeding through the cooler winter rest. In practice that is every 2-4 weeks at most, only between spring through early autumn (roughly March to September) — never in the dormant winter months.
What strength of feed for fishbone cactus?
Quarter strength is the rule for fishbone cactus. A full-strength dose is a fast route to scorched roots; when unsure, skip a feed entirely rather than double up.
What does over-feeding fishbone cactus look like?
A white or yellowish salt crust on the soil surface or pot rim. Brown, scorched leaf tips or margins despite normal watering. Soft, stretched, floppy growth that flops instead of standing firm. Roots that look burnt or brown when you next repot. Over-feeding is the number-one fertiliser mistake with fishbone cactus. It does not want a lush growth spurt — extra nitrogen makes it weak, etiolated and rot-prone, the opposite of the tough plant you bought.
Should I flush the soil of fishbone cactus?
Because you feed so rarely, salts still creep up over time. Flush the pot of fishbone cactus with plain water until it runs freely from the base once or twice a year — and always repot into fresh gritty mix every 2-3 years rather than relying on feed.
Keep reading
- Fishbone Cactus care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water fishbone cactus — 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 snake plant
- How to fertilise dracaena
- How to fertilise peperomia
- All 1284 fertilising guides in the Growli library