Fertilising guide
How to fertilise Maltese cross (Lychnis chalcedonica)— schedule & NPK
Also called Maltese cross, Jerusalem cross, Scarlet lightning, Flower of Bristol.
More about maltese cross
About Maltese cross
Lychnis chalcedonica · also called Maltese cross, Jerusalem cross · flowering
A striking cottage-garden perennial bearing tight, flat-topped clusters of vivid scarlet-red flowers with distinctive cross-shaped petals on tall, upright stems in early to midsummer. Thrives in moist, fertile soil in sun or partial shade. Considered pet-safe. Bold and long-flowering, it partners well with blue and yellow perennials.
Growth habit: Upright, clump-forming herbaceous perennial with erect, slightly hairy, leafy stems. Opposite, ovate-lanceolate leaves. Dense, flat-topped corymbs of brilliant scarlet flowers, each with four notched petals arranged in a cross shape, appear in June–July.
What fertiliser maltese cross actually wants — and why
Maltese cross 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 maltese cross: 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 maltese cross, 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 maltese cross:
Apply a balanced granular fertiliser in early spring to support strong stem growth and prolific flowering. A light balanced feed after the first flush of flowers can encourage a secondary bloom period in some seasons. 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 maltese cross 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 maltese cross
Half strength is the safe default for maltese cross — 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 maltese cross first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the maltese cross watering schedule.
Signs you are over-feeding maltese cross
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for maltese cross:
- 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 maltese cross
- 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 maltese cross care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of maltese cross 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 maltese cross
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 maltese cross — frequently asked questions
What fertiliser does maltese cross 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. Maltese cross 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 maltese cross?
Apply a balanced granular fertiliser in early spring to support strong stem growth and prolific flowering. A light balanced feed after the first flush of flowers can encourage a secondary bloom period in some seasons. Apply a balanced granular fertiliser in early spring to support strong stem growth and prolific flowering. A light balanced feed after the first flush of flowers can encourage a secondary bloom period in some seasons. 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 maltese cross?
Half strength is the safe default for maltese cross — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding maltese cross 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 maltese cross 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 maltese cross?
Flush the pot of maltese cross 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
- Maltese cross care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water maltese cross — 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 polystichum makinoi
- How to fertilise polystichum neolobatum
- How to fertilise athyrium niponicum 'red beauty'
- All 6887 fertilising guides in the Growli library