Fertilising guide
How to fertilise Guernsey Lily (Nerine sarniensis)— schedule & NPK
Also called Scarlet Guernsey Lily, Cape Colony Lily, Jersey Lily.
More about guernsey lily
About Guernsey Lily
Nerine sarniensis · also called Scarlet Guernsey Lily, Cape Colony Lily · flowering
Nerine sarniensis is a South African bulb famed for its dazzling scarlet, salmon, or pink iridescent flowers — each petal catches light like spun glass. Produces flowers in early autumn before leaves appear. Less hardy than N. bowdenii and best grown under glass in the UK. Toxic to pets due to Amaryllidaceae alkaloids concentrated in the bulb.
Growth habit: Deciduous bulbous perennial with an inverted summer-dormancy growth cycle
Watch for — Bulb scale mite: Minute mites infest the scales of stored bulbs, causing stunted, distorted foliage. Dip newly acquired bulbs in a miticide solution before planting.
What fertiliser guernsey lily actually wants — and why
Guernsey Lily 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 guernsey 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 guernsey 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 guernsey lily:
Apply a high-potassium liquid fertiliser (tomato feed at half strength) monthly from the time foliage is established in autumn until foliage begins to yellow in late spring. Never feed during summer dormancy. Treat that as monthly 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 guernsey 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 guernsey lily
Half strength is the safe default for guernsey lily — 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 guernsey lily first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the guernsey lily watering schedule.
Signs you are over-feeding guernsey lily
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for guernsey lily:
- 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 guernsey lily
- 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 guernsey lily care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of guernsey lily 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 guernsey lily
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 guernsey lily — frequently asked questions
What fertiliser does guernsey lily 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. Guernsey Lily 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 guernsey lily?
Apply a high-potassium liquid fertiliser (tomato feed at half strength) monthly from the time foliage is established in autumn until foliage begins to yellow in late spring. Never feed during summer dormancy. Apply a high-potassium liquid fertiliser (tomato feed at half strength) monthly from the time foliage is established in autumn until foliage begins to yellow in late spring. Never feed during summer dormancy. Treat that as monthly 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 guernsey lily?
Half strength is the safe default for guernsey lily — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding guernsey lily 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 guernsey lily 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 guernsey lily?
Flush the pot of guernsey lily 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
- Guernsey Lily care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water guernsey 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 hungarian oak
- How to fertilise turkey oak
- How to fertilise downy oak
- All 11687 fertilising guides in the Growli library