Fertilising guide
How to fertilise Amaryllis (Hippeastrum hybrids)— schedule & NPK
Also called Amaryllis, Dutch amaryllis, Knight's star lily, Barbados lily, Fire lily.
More about amaryllis
About Amaryllis
Hippeastrum hybrids · also called Amaryllis, Dutch amaryllis · flowering
Amaryllis (Hippeastrum hybrids) is a tender bulb prized for huge trumpet flowers on tall leafless stalks, popular for winter forcing indoors. It wants bright light, warm rooms, and sparing watering until growth starts. The ASPCA lists it as toxic to cats and dogs, so keep bulbs and plants out of reach.
Growth habit: Bulbous perennial that sends up one or more thick, leafless flower stalks topped with 2-6 large trumpet blooms, followed by long strap-shaped leaves. Grown indoors it follows a yearly cycle of bloom, leafy growth, and a dormant rest period.
Watch for — Tall stalk but no leaves or flowers: Bulb may be undersized, exhausted, or stored too warm. Give bright light and consistent feeding after blooming so the bulb can recharge, and provide a proper cool dormancy before forcing again.
What fertiliser amaryllis actually wants — and why
Amaryllis 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 amaryllis: 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 amaryllis, 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 amaryllis:
Feed once new growth is visible, using a balanced or higher-phosphorus houseplant fertiliser at half strength roughly every two weeks (or each watering at quarter strength). Continue feeding the strap-like leaves after flowering to recharge the bulb for next season, then stop before the dormant rest. 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 amaryllis 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 amaryllis
Half strength is the safe default for amaryllis — 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 amaryllis first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the amaryllis watering schedule.
Signs you are over-feeding amaryllis
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for amaryllis:
- 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 amaryllis
- 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 amaryllis care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of amaryllis 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 amaryllis
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 amaryllis — frequently asked questions
What fertiliser does amaryllis 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. Amaryllis 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 amaryllis?
Feed once new growth is visible, using a balanced or higher-phosphorus houseplant fertiliser at half strength roughly every two weeks (or each watering at quarter strength). Continue feeding the strap-like leaves after flowering to recharge the bulb for next season, then stop before the dormant rest. Feed once new growth is visible, using a balanced or higher-phosphorus houseplant fertiliser at half strength roughly every two weeks (or each watering at quarter strength). Continue feeding the strap-like leaves after flowering to recharge the bulb for next season, then stop before the dormant rest. 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 amaryllis?
Half strength is the safe default for amaryllis — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding amaryllis 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 amaryllis 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 amaryllis?
Flush the pot of amaryllis 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
- Amaryllis care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water amaryllis — 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 609 fertilising guides in the Growli library