Fertilising guide
How to fertilise Crossandra (firecracker flower) (Crossandra infundibuliformis)— schedule & NPK
Also called firecracker flower, firecracker plant.
More about crossandra (firecracker flower)
About Crossandra (firecracker flower)
Crossandra infundibuliformis · also called firecracker flower, firecracker plant · flowering
Crossandra is a tender tropical from the acanthus family, grown indoors for its fan-shaped orange, salmon or coral flowers that appear almost year-round. It wants bright indirect light, warmth and steadily moist soil. The ASPCA lists Crossandra as non-toxic to cats, dogs and horses, so it is pet-safe.
Growth habit: Compact, bushy evergreen sub-shrub with glossy dark-green leaves and upright flower spikes
Watch for — Mealybugs, aphids and whitefly: Sap-feeding insects that cluster on new growth and leaf undersides, leaving sticky honeydew and sometimes sooty mould.
What fertiliser crossandra (firecracker flower) actually wants — and why
Crossandra (firecracker flower) 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 crossandra (firecracker flower): 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 crossandra (firecracker flower), 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 crossandra (firecracker flower):
Feed every 2 weeks through spring and summer with a balanced water-soluble houseplant fertiliser at half strength; a feed with a little extra potassium supports flowering. Stop or reduce feeding in autumn and winter while growth slows. Treat that as every 2 weeks 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 crossandra (firecracker flower) 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 crossandra (firecracker flower)
Half strength is the safe default for crossandra (firecracker flower) — 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 crossandra (firecracker flower) first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the crossandra (firecracker flower) watering schedule.
Signs you are over-feeding crossandra (firecracker flower)
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for crossandra (firecracker flower):
- 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 crossandra (firecracker flower)
- 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 crossandra (firecracker flower) care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of crossandra (firecracker flower) 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 crossandra (firecracker flower)
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 crossandra (firecracker flower) — frequently asked questions
What fertiliser does crossandra (firecracker flower) 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. Crossandra (firecracker flower) 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 crossandra (firecracker flower)?
Feed every 2 weeks through spring and summer with a balanced water-soluble houseplant fertiliser at half strength; a feed with a little extra potassium supports flowering. Stop or reduce feeding in autumn and winter while growth slows. Feed every 2 weeks through spring and summer with a balanced water-soluble houseplant fertiliser at half strength; a feed with a little extra potassium supports flowering. Stop or reduce feeding in autumn and winter while growth slows. Treat that as every 2 weeks 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 crossandra (firecracker flower)?
Half strength is the safe default for crossandra (firecracker flower) — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding crossandra (firecracker flower) 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 crossandra (firecracker flower) 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 crossandra (firecracker flower)?
Flush the pot of crossandra (firecracker flower) 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
- Crossandra (firecracker flower) care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water crossandra (firecracker flower) — 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 271 fertilising guides in the Growli library