Fertilising guide
How to fertilise Wild Teasel (Dipsacus fullonum)— schedule & NPK
Also called Wild Teasel, Common Teasel, Fuller's Teasel.
More about wild teasel
About Wild Teasel
Dipsacus fullonum · also called Wild Teasel, Common Teasel · flowering
Native to Britain, Ireland, and mainland Europe, wild teasel is a robust biennial of roadsides, riverbanks, and rough grassland, growing a prickly basal rosette in year one and a towering spiny stem with cone-shaped flowerheads in year two. It thrives in full sun to partial shade on moist, fertile soils including heavy clay, and is prized in wildlife gardens for its violet-band flowers that attract bees and its architectural seedheads that goldfinches work through autumn and winter. The single most critical care note is that it self-seeds prolifically and can naturalise aggressively, so deadhead promptly if spread is unwanted. No toxicity to dogs, cats, or horses has been reported for this species.
Growth habit: Biennial; forms a flat prickly rosette in year one, then sends up a spiny, branched stem to 2.5 m in year two before dying after setting seed.
What fertiliser wild teasel actually wants — and why
Wild Teasel 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 wild teasel: 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 wild teasel, 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 wild teasel:
Feed is unnecessary — plants in rich soil will be lush but may flop; lean soils produce sturdier stems. 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 wild teasel 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 wild teasel
Half strength is the safe default for wild teasel — 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 wild teasel first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the wild teasel watering schedule.
Signs you are over-feeding wild teasel
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for wild teasel:
- 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 wild teasel
- 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 wild teasel care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of wild teasel 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 wild teasel
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 wild teasel — frequently asked questions
What fertiliser does wild teasel 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. Wild Teasel 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 wild teasel?
Feed is unnecessary — plants in rich soil will be lush but may flop; lean soils produce sturdier stems. Feed is unnecessary — plants in rich soil will be lush but may flop; lean soils produce sturdier stems. 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 wild teasel?
Half strength is the safe default for wild teasel — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding wild teasel 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 wild teasel 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 wild teasel?
Flush the pot of wild teasel 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
- Wild Teasel care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water wild teasel — 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 bladder cherry
- How to fertilise olympic st. john's wort
- How to fertilise shrubby st. john's wort
- All 10153 fertilising guides in the Growli library