Fertilising guide
How to fertilise Red Spider Lily (Lycoris radiata)— schedule & NPK
Also called Red spider lily, Hurricane lily, Surprise lily, Equinox flower, Naked lily, Higanbana, Red magic lily.
More about red spider lily
About Red Spider Lily
Lycoris radiata · also called Red spider lily, Hurricane lily · flowering
Red spider lily (Lycoris radiata) is an autumn-flowering bulb in the amaryllis family, sending up leafless stems of fiery, spidery red blooms before its strap-like leaves appear. It is toxic to cats and dogs: every part contains the alkaloid lycorine, with the bulb most potent. Keep pets and children away and verify any exposure with your vet.
Growth habit: Clump-forming, hysteranthous bulbous perennial: leafless flower scapes emerge in late summer to early autumn carrying umbels of curled, reflexed red flowers with long, conspicuous stamens, followed by strap-shaped grey-green leaves that persist through winter and die back in late spring. Spreads slowly by bulb offsets and naturalises over time.
Watch for — Stunted or blackened foliage in cold areas: The winter-persistent leaves are frost-tender, so hard freezes can damage the foliage and weaken next year's flowering in this half-hardy (H3) bulb.
What fertiliser red spider lily actually wants — and why
Red Spider Lily feeds for next year, not this one — the critical window is after flowering, while the leaves are still green and recharging the bulb.
A low-nitrogen, potassium- and phosphorus-leaning bulb fertiliser (something like 5-10-10) or bonemeal at planting. High nitrogen grows floppy leaves and rots stored bulbs.
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 red spider lily: 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 red spider lily, 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 red spider lily:
Feed lightly. Apply a balanced, low-nitrogen bulb fertiliser in autumn as flower scapes and then leaves emerge, and again in late winter while foliage is active. Avoid heavy nitrogen, which encourages leaves at the expense of flowers. No feeding is needed during summer dormancy. The rhythm: a bulb feed at planting, a light feed as leaves emerge, and — most important — a potassium feed straight after flowering while the foliage is still green and feeding the bulb. Never cut the leaves off early.
The dormant-season rule matters more than the exact interval: skip feeding entirely when red spider lily 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 red spider lily
Use the bulb-feed label rate for red spider lily; the timing (post-bloom, leaves still green) does far more for next year's display than the concentration.
Feeding always goes onto already-damp soil, never dry roots — water red spider lily first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the red spider lily watering schedule.
Signs you are over-feeding red spider lily
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for red spider lily:
- Tall, floppy, soft leaves that flop over (too much nitrogen).
- Soft or rotting bulbs lifted at the end of the season.
- Lush foliage but few or poor flowers.
Signs you are under-feeding red spider lily
- Progressively fewer or smaller flowers year on year ("going blind").
- Small, weak bulbs and thin foliage.
- Bulbs that fail to come back at all after a few seasons.
If the symptoms point at watering, light or roots rather than nutrition, the full red spider lily care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Bulbs are not container-flushed like houseplants; the equivalent is not over-feeding and lifting/dividing congested clumps of red spider lily every few years so they are not competing for nutrients.
Organic vs synthetic feeds for red spider lily
Organic options
Bonemeal worked in at planting plus a mulch of garden compost or well-rotted leaf-mould is the traditional, reliable approach for red spider lily. UK: blood, fish & bone or Westland Bulb Food; US: Espoma Bulb-tone or bonemeal.
Synthetic / liquid feeds
A proprietary bulb fertiliser at planting and a high-potash liquid (tomato feed) after flowering — UK: Westland Bulb Food then Tomorite; US: Miracle-Gro Shake 'n Feed Bulb or a bloom booster post-flower.
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 red spider lily — frequently asked questions
What fertiliser does red spider lily need?
A low-nitrogen, potassium- and phosphorus-leaning bulb fertiliser (something like 5-10-10) or bonemeal at planting. High nitrogen grows floppy leaves and rots stored bulbs. Red Spider Lily feeds for next year, not this one — the critical window is after flowering, while the leaves are still green and recharging the bulb.
How often should I feed red spider lily?
Feed lightly. Apply a balanced, low-nitrogen bulb fertiliser in autumn as flower scapes and then leaves emerge, and again in late winter while foliage is active. Avoid heavy nitrogen, which encourages leaves at the expense of flowers. No feeding is needed during summer dormancy. Feed lightly. Apply a balanced, low-nitrogen bulb fertiliser in autumn as flower scapes and then leaves emerge, and again in late winter while foliage is active. Avoid heavy nitrogen, which encourages leaves at the expense of flowers. No feeding is needed during summer dormancy. The rhythm: a bulb feed at planting, a light feed as leaves emerge, and — most important — a potassium feed straight after flowering while the foliage is still green and feeding the bulb. Never cut the leaves off early.
What strength of feed for red spider lily?
Use the bulb-feed label rate for red spider lily; the timing (post-bloom, leaves still green) does far more for next year's display than the concentration.
What does over-feeding red spider lily look like?
Tall, floppy, soft leaves that flop over (too much nitrogen). Soft or rotting bulbs lifted at the end of the season. Lush foliage but few or poor flowers. Cutting or tying off the leaves of red spider lily as soon as the flowers fade is the great bulb mistake — the bulb recharges through those leaves for weeks afterward, and removing them early means a weak or blind display next year.
Should I flush the soil of red spider lily?
Bulbs are not container-flushed like houseplants; the equivalent is not over-feeding and lifting/dividing congested clumps of red spider lily every few years so they are not competing for nutrients.
Keep reading
- Red Spider Lily care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water red spider lily — 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 271 fertilising guides in the Growli library