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Fertilising guide

How to fertilise Round-Leaf Calathea (Calathea orbifolia)— schedule & NPK

Also called round-leaf calathea, orbifolia calathea, prayer plant.

More about round-leaf calathea

About Round-Leaf Calathea

Calathea orbifolia · also called round-leaf calathea, orbifolia calathea · houseplant

Calathea orbifolia is one of the most visually bold prayer plants, producing large rounded leaves up to 30 cm across with elegant silver-green striping. A high-humidity, low-fuss houseplant ideal for bathrooms or rooms with humidifiers; propagation is by division only, making it a slow-to-multiply collector's plant.

Growth habit: Clump-forming, upright rosette with large rounded leaves; leaves fold slightly at night (nyctinastic movement)

What fertiliser round-leaf calathea actually wants — and why

Round-Leaf Calathea 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 round-leaf calathea: 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 round-leaf calathea, 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 round-leaf calathea:

Apply half-strength balanced liquid fertilizer (10-10-10 or 20-20-20) every 4–6 weeks from spring through summer. Do not feed in autumn or winter. Excess fertilizer causes salt accumulation and brown leaf tips; flush soil with plain water every few months. 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 round-leaf calathea 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 round-leaf calathea

Half strength is the safe default for round-leaf calathea — 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 round-leaf calathea first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the round-leaf calathea watering schedule.

Signs you are over-feeding round-leaf calathea

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for round-leaf calathea:

Signs you are under-feeding round-leaf calathea

If the symptoms point at watering, light or roots rather than nutrition, the full round-leaf calathea care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush the pot of round-leaf calathea 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 round-leaf calathea

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 round-leaf calathea — frequently asked questions

What fertiliser does round-leaf calathea 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. Round-Leaf Calathea 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 round-leaf calathea?

Apply half-strength balanced liquid fertilizer (10-10-10 or 20-20-20) every 4–6 weeks from spring through summer. Do not feed in autumn or winter. Excess fertilizer causes salt accumulation and brown leaf tips; flush soil with plain water every few months. Apply half-strength balanced liquid fertilizer (10-10-10 or 20-20-20) every 4–6 weeks from spring through summer. Do not feed in autumn or winter. Excess fertilizer causes salt accumulation and brown leaf tips; flush soil with plain water every few months. 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 round-leaf calathea?

Half strength is the safe default for round-leaf calathea — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

What does over-feeding round-leaf calathea 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 round-leaf calathea 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 round-leaf calathea?

Flush the pot of round-leaf calathea 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.

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