Fertilising guide
How to fertilise Spiritus Sancti (Philodendron spiritus-sancti)— schedule & NPK
Also called Spiritus Sancti, Ghost Philodendron.
More about spiritus sancti
About Spiritus Sancti
Philodendron spiritus-sancti · also called Spiritus Sancti, Ghost Philodendron · houseplant
Philodendron spiritus-sancti is an exceptionally rare Brazilian species with long, pendulous, narrow arrow-shaped leaves and a famously high collector value. Critically endangered in the wild, it's a slow climbing aroid demanding warmth, high humidity, and bright indirect light. Beautiful and coveted, but like all philodendrons toxic to cats and dogs.
Growth habit: Slow-growing climbing aroid with long, narrow, drooping arrow-shaped leaves on an upright stem.
What fertiliser spiritus sancti actually wants — and why
Spiritus Sancti is a genuinely hungry tropical — in bright warmth it pushes growth fast and rewards a regular half-strength balanced feed all season.
A balanced liquid feed (even N-P-K) or a slightly nitrogen-leaning foliage feed — this is a big-leaved foliage plant putting on real size, so it wants steady nitrogen for lush leaves, not a bloom 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 spiritus sancti: 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 spiritus sancti, 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 spiritus sancti:
Feed every 3-4 weeks in the growing season with a balanced liquid fertiliser at half strength; this slow grower needs only gentle feeding. Pause in winter and flush regularly, as the sensitive roots dislike salt accumulation. For a fast grower like this that means feeding regularly — about every 3-4 weeks — right through spring through early autumn (roughly March to September), tapering off only as light drops in autumn.
The dormant-season rule matters more than the exact interval: skip feeding entirely when spiritus sancti 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 spiritus sancti
Half strength every feed is the sweet spot for spiritus sancti: frequent enough to fuel fast growth, dilute enough that it never scorches even when you feed often.
Feeding always goes onto already-damp soil, never dry roots — water spiritus sancti first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the spiritus sancti watering schedule.
Signs you are over-feeding spiritus sancti
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for spiritus sancti:
- Brown, scorched leaf tips and margins despite correct watering.
- A white salt crust on the soil or around the pot edge.
- Sudden leaf yellowing and drop shortly after a strong feed.
- Soft, weak, over-stretched growth that cannot support itself.
Signs you are under-feeding spiritus sancti
- New leaves coming in noticeably smaller than older ones.
- Pale, yellow-green older leaves and slow growth through peak summer.
- A general loss of vigour and gloss in a plant that should be racing away.
If the symptoms point at watering, light or roots rather than nutrition, the full spiritus sancti care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Because you feed often, salts accumulate faster — flush the pot of spiritus sancti with plain water until it drains freely roughly every month through the feeding season to keep the root zone clean.
Organic vs synthetic feeds for spiritus sancti
Organic options
A diluted seaweed or fish-and-seaweed feed plus a yearly top-dress of worm castings supports fast growth without burn risk. UK: Westland seaweed or Baby Bio Organic; US: Neptune's Harvest or Espoma Indoor!.
Synthetic / liquid feeds
A balanced houseplant liquid at half strength applied frequently — UK: Baby Bio, Phostrogen or Westland Houseplant Feed; US: Miracle-Gro Indoor Plant Food or Dyna-Gro Foliage-Pro for steady leafy growth.
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 spiritus sancti — frequently asked questions
What fertiliser does spiritus sancti need?
A balanced liquid feed (even N-P-K) or a slightly nitrogen-leaning foliage feed — this is a big-leaved foliage plant putting on real size, so it wants steady nitrogen for lush leaves, not a bloom formula. Spiritus Sancti is a genuinely hungry tropical — in bright warmth it pushes growth fast and rewards a regular half-strength balanced feed all season.
How often should I feed spiritus sancti?
Feed every 3-4 weeks in the growing season with a balanced liquid fertiliser at half strength; this slow grower needs only gentle feeding. Pause in winter and flush regularly, as the sensitive roots dislike salt accumulation. Feed every 3-4 weeks in the growing season with a balanced liquid fertiliser at half strength; this slow grower needs only gentle feeding. Pause in winter and flush regularly, as the sensitive roots dislike salt accumulation. For a fast grower like this that means feeding regularly — about every 3-4 weeks — right through spring through early autumn (roughly March to September), tapering off only as light drops in autumn.
What strength of feed for spiritus sancti?
Half strength every feed is the sweet spot for spiritus sancti: frequent enough to fuel fast growth, dilute enough that it never scorches even when you feed often.
What does over-feeding spiritus sancti look like?
Brown, scorched leaf tips and margins despite correct watering. A white salt crust on the soil or around the pot edge. Sudden leaf yellowing and drop shortly after a strong feed. Soft, weak, over-stretched growth that cannot support itself. The mistake here is the opposite of most houseplants: under-feeding a fast tropical in peak season starves it, leaving small, pale new leaves and slow growth — but full-strength doses still burn it, so feed often and weak, not occasionally and strong.
Should I flush the soil of spiritus sancti?
Because you feed often, salts accumulate faster — flush the pot of spiritus sancti with plain water until it drains freely roughly every month through the feeding season to keep the root zone clean.
Keep reading
- Spiritus Sancti care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water spiritus sancti — 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 2464 fertilising guides in the Growli library