Fertilising guide
How to fertilise Aztec Lily (Sprekelia formosissima)— schedule & NPK
Also called Aztec lily, Jacobean lily, Maltese cross lily.
More about aztec lily
About Aztec Lily
Sprekelia formosissima · also called Aztec lily, Jacobean lily · flowering
Sprekelia formosissima is a striking bulbous perennial from Mexico and Guatemala, producing large, deep crimson, orchid-like flowers on bare stems in spring or early summer before the strap-like foliage fully develops. It demands full sun, excellent drainage, and a dry rest period after foliage dies back in autumn to set flower buds for the following season. In the UK it is best kept in a frost-free glasshouse or as a conservatory pot plant; in the US it can be grown outdoors year-round in zones 8–11. All parts of this plant are toxic to cats and dogs.
Growth habit: Bulbous perennial producing one to three leafless flower stems per bulb in spring, followed by strap-shaped leaves to 40 cm that persist through summer.
What fertiliser aztec lily actually wants — and why
Aztec Lily 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 aztec 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 aztec 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 aztec lily:
Feed every two weeks with a balanced liquid fertiliser from leaf emergence until flowering; switch to a high-potassium feed after flowers fade to build up the bulb, then stop as leaves yellow. 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 aztec 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 aztec lily
Half strength is the safe default for aztec lily — 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 aztec lily first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the aztec lily watering schedule.
Signs you are over-feeding aztec lily
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for aztec lily:
- 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 aztec lily
- 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 aztec lily care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of aztec lily 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 aztec lily
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 aztec lily — frequently asked questions
What fertiliser does aztec lily 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. Aztec Lily 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 aztec lily?
Feed every two weeks with a balanced liquid fertiliser from leaf emergence until flowering; switch to a high-potassium feed after flowers fade to build up the bulb, then stop as leaves yellow. Feed every two weeks with a balanced liquid fertiliser from leaf emergence until flowering; switch to a high-potassium feed after flowers fade to build up the bulb, then stop as leaves yellow. 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 aztec lily?
Half strength is the safe default for aztec lily — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding aztec lily 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 aztec lily 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 aztec lily?
Flush the pot of aztec lily 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
- Aztec Lily care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water aztec lily — 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 honesty
- How to fertilise thoroughwax
- How to fertilise billy buttons
- All 10153 fertilising guides in the Growli library