Fertilising guide
How to fertilise Tiger Orchid (Grammatophyllum speciosum)— schedule & NPK
Also called Giant Orchid, Queen of Orchids.
More about tiger orchid
About Tiger Orchid
Grammatophyllum speciosum · also called Giant Orchid, Queen of Orchids · flowering
Grammatophyllum speciosum is the world's largest orchid, a massive Southeast Asian epiphyte whose clumps can weigh hundreds of kilograms and send up towering spikes of dozens of tiger-spotted, maroon-on-yellow blooms. It demands strong light, abundant warmth, water and feeding during the monsoon-like growth, then a drier rest, and is grown by serious collectors as a long-term, slow-to-flower specimen.
Growth habit: Sympodial epiphyte forming enormous clumps of long, cane-like pseudobulbs clothed in strap leaves. Mature plants send up tall, erect or arching spikes from the base bearing dozens of large, long-lasting tiger-marked flowers; clumps can become massive and very heavy.
Watch for — Leaf scorch: Bleached or burnt patches when moved too quickly into strong sun. Increase light gradually so leaves acclimate to high intensity.
What fertiliser tiger orchid actually wants — and why
Tiger Orchid 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.
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.
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 tiger orchid: 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 tiger orchid, 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 tiger orchid:
Feed generously during active growth with a balanced orchid fertiliser at half strength every one to two weeks, as this huge plant is a heavy feeder; a higher-phosphorus feed can be used as canes mature. Flush regularly and reduce feeding during the dry rest. The pattern that matters: feed little and often through active growth and budding — sparingly through the growing season — 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 tiger orchid 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 tiger orchid
Very dilute — quarter strength, the classic "weakly, weekly" approach for tiger orchid. 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 tiger orchid first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the tiger orchid watering schedule.
Signs you are over-feeding tiger orchid
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for tiger orchid:
- 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 tiger orchid
- 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 tiger orchid 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 tiger orchid 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 tiger orchid
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 tiger orchid — frequently asked questions
What fertiliser does tiger orchid 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. Tiger Orchid 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 tiger orchid?
Feed generously during active growth with a balanced orchid fertiliser at half strength every one to two weeks, as this huge plant is a heavy feeder; a higher-phosphorus feed can be used as canes mature. Flush regularly and reduce feeding during the dry rest. Feed generously during active growth with a balanced orchid fertiliser at half strength every one to two weeks, as this huge plant is a heavy feeder; a higher-phosphorus feed can be used as canes mature. Flush regularly and reduce feeding during the dry rest. The pattern that matters: feed little and often through active growth and budding — sparingly through the growing season — and ease right off during the rest period that triggers the next flush.
What strength of feed for tiger orchid?
Very dilute — quarter strength, the classic "weakly, weekly" approach for tiger orchid. These plants have fine roots that scorch easily and a steady trickle beats an occasional strong dose for flowering.
What does over-feeding tiger orchid 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 tiger orchid 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 tiger orchid?
Specialist and bloom feeds leave salts that scorch fine roots — flush tiger orchid thoroughly with plain water until it runs clear every 4-6 weeks in the feeding season, and always between feeds for orchids.
Keep reading
- Tiger Orchid care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water tiger orchid — 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 1284 fertilising guides in the Growli library