Fertilising guide
How to fertilise Pseuderanthemum carruthersii (Pseuderanthemum carruthersii)— schedule & NPK
Also called Pseuderanthemum, Variegated false eranthemum.
More about pseuderanthemum carruthersii
About Pseuderanthemum carruthersii
Pseuderanthemum carruthersii · also called Pseuderanthemum, Variegated false eranthemum · tropical
Pseuderanthemum carruthersii is a tropical evergreen shrub in the Acanthaceae, grown for bold foliage variegated in purple, pink, green, and cream, and small flowers that draw butterflies. Tougher than the jewel-plant terrarium species, it wants bright indirect light, warmth, and moderate humidity, tolerating brief drying. It makes an upright accent indoors and a landscape shrub in frost-free climates.
Growth habit: Upright, branching evergreen shrub that can be pinched and pruned to stay bushy and compact.
What fertiliser pseuderanthemum carruthersii actually wants — and why
Pseuderanthemum carruthersii 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 pseuderanthemum carruthersii: 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 pseuderanthemum carruthersii, 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 pseuderanthemum carruthersii:
Feed every 2-4 weeks through spring and summer with a balanced houseplant fertiliser to support colourful foliage; reduce to occasional feeding in winter. Treat that as every 2-4 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 pseuderanthemum carruthersii 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 pseuderanthemum carruthersii
Half strength is the safe default for pseuderanthemum carruthersii — 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 pseuderanthemum carruthersii first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the pseuderanthemum carruthersii watering schedule.
Signs you are over-feeding pseuderanthemum carruthersii
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for pseuderanthemum carruthersii:
- 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 pseuderanthemum carruthersii
- 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 pseuderanthemum carruthersii care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of pseuderanthemum carruthersii 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 pseuderanthemum carruthersii
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 pseuderanthemum carruthersii — frequently asked questions
What fertiliser does pseuderanthemum carruthersii 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. Pseuderanthemum carruthersii 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 pseuderanthemum carruthersii?
Feed every 2-4 weeks through spring and summer with a balanced houseplant fertiliser to support colourful foliage; reduce to occasional feeding in winter. Feed every 2-4 weeks through spring and summer with a balanced houseplant fertiliser to support colourful foliage; reduce to occasional feeding in winter. Treat that as every 2-4 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 pseuderanthemum carruthersii?
Half strength is the safe default for pseuderanthemum carruthersii — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding pseuderanthemum carruthersii 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 pseuderanthemum carruthersii 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 pseuderanthemum carruthersii?
Flush the pot of pseuderanthemum carruthersii 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
- Pseuderanthemum carruthersii care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water pseuderanthemum carruthersii — 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 monstera
- How to fertilise pothos
- How to fertilise fiddle leaf fig
- All 5561 fertilising guides in the Growli library