Fertilising guide
How to fertilise Spiked Kohleria (Kohleria spicata)— schedule & NPK
Also called Spiked Kohleria, Spike-Flowered Kohleria.
More about spiked kohleria
About Spiked Kohleria
Kohleria spicata · also called Spiked Kohleria, Spike-Flowered Kohleria · tropical
Kohleria spicata is a robust, rhizomatous gesneriad from Central America and northern South America, bearing spikes of pendulous, tubular red to orange-red flowers with yellow interiors spotted in purple. Softly hairy stems and dark-green, velvety leaves add tropical appeal. It thrives in warm, humid conditions with bright indirect light and grows vigorously in summer.
Growth habit: Upright, rhizomatous herbaceous perennial producing tall flowering spikes; may die back partially in winter
What fertiliser spiked kohleria actually wants — and why
Spiked Kohleria 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 spiked kohleria: 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 spiked kohleria, 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 spiked kohleria:
Feed every 2 weeks during spring and summer with a high-potassium liquid fertiliser (such as a tomato formula) diluted to half strength to maximise flower spike production. Use a balanced formula monthly in early spring to support initial growth. No fertiliser during dormancy. Treat that as every 2 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 spiked kohleria 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 spiked kohleria
Half strength is the safe default for spiked kohleria — 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 spiked kohleria first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the spiked kohleria watering schedule.
Signs you are over-feeding spiked kohleria
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for spiked kohleria:
- 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 spiked kohleria
- 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 spiked kohleria care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of spiked kohleria 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 spiked kohleria
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 spiked kohleria — frequently asked questions
What fertiliser does spiked kohleria 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. Spiked Kohleria 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 spiked kohleria?
Feed every 2 weeks during spring and summer with a high-potassium liquid fertiliser (such as a tomato formula) diluted to half strength to maximise flower spike production. Use a balanced formula monthly in early spring to support initial growth. No fertiliser during dormancy. Feed every 2 weeks during spring and summer with a high-potassium liquid fertiliser (such as a tomato formula) diluted to half strength to maximise flower spike production. Use a balanced formula monthly in early spring to support initial growth. No fertiliser during dormancy. Treat that as every 2 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 spiked kohleria?
Half strength is the safe default for spiked kohleria — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding spiked kohleria 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 spiked kohleria 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 spiked kohleria?
Flush the pot of spiked kohleria 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
- Spiked Kohleria care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water spiked kohleria — 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 colocasia 'coffee cups'
- How to fertilise typhonodorum lindleyanum
- How to fertilise dracontium polyphyllum
- All 8452 fertilising guides in the Growli library