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Fertilising guide

How to fertilise Zantedeschia 'Edge of Night' (Zantedeschia 'Edge of Night')— schedule & NPK

Also called Edge of Night calla lily, deep purple calla.

More about zantedeschia 'edge of night'

About Zantedeschia 'Edge of Night'

Zantedeschia 'Edge of Night' · also called Edge of Night calla lily, deep purple calla · flowering

Zantedeschia 'Edge of Night' is a hybrid calla lily prized for near-black, velvety purple flowers above glossy spotted foliage. A tender tuberous perennial, it loves warmth, bright light and moist, fertile, well-drained soil. Lift the rhizome before frost in cold climates and store dry. Striking in containers and summer borders, it reaches around 50-60 cm.

Growth habit: Tender rhizomatous perennial forming a clump of upright arrow-shaped leaves with funnel-shaped spathes held on slender stems; dies back to the rhizome in winter.

Watch for — All leaves, few flowers: Too much nitrogen or too little light reduces blooming. Switch to a higher-potassium feed and give full sun to bright light.

What fertiliser zantedeschia 'edge of night' actually wants — and why

Zantedeschia 'Edge of Night' 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 zantedeschia 'edge of night': 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 zantedeschia 'edge of night', 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 zantedeschia 'edge of night':

Feed every 2-3 weeks during active growth with a balanced or slightly potassium-rich liquid feed to support flowering. Avoid excess nitrogen, which favours leaves over blooms. Stop feeding as the plant enters dormancy. Treat that as every 2-3 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 zantedeschia 'edge of night' 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 zantedeschia 'edge of night'

Half strength is the safe default for zantedeschia 'edge of night' — 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 zantedeschia 'edge of night' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the zantedeschia 'edge of night' watering schedule.

Signs you are over-feeding zantedeschia 'edge of night'

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for zantedeschia 'edge of night':

Signs you are under-feeding zantedeschia 'edge of night'

If the symptoms point at watering, light or roots rather than nutrition, the full zantedeschia 'edge of night' care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush the pot of zantedeschia 'edge of night' 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 zantedeschia 'edge of night'

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 zantedeschia 'edge of night' — frequently asked questions

What fertiliser does zantedeschia 'edge of night' 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. Zantedeschia 'Edge of Night' 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 zantedeschia 'edge of night'?

Feed every 2-3 weeks during active growth with a balanced or slightly potassium-rich liquid feed to support flowering. Avoid excess nitrogen, which favours leaves over blooms. Stop feeding as the plant enters dormancy. Feed every 2-3 weeks during active growth with a balanced or slightly potassium-rich liquid feed to support flowering. Avoid excess nitrogen, which favours leaves over blooms. Stop feeding as the plant enters dormancy. Treat that as every 2-3 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 zantedeschia 'edge of night'?

Half strength is the safe default for zantedeschia 'edge of night' — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

What does over-feeding zantedeschia 'edge of night' 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 zantedeschia 'edge of night' 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 zantedeschia 'edge of night'?

Flush the pot of zantedeschia 'edge of night' 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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