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Fertilising guide

How to fertilise Cow Parsley (Anthriscus sylvestris)— schedule & NPK

Also called Cow Parsley, Wild Chervil, Queen Anne's Lace, Keck.

More about cow parsley

About Cow Parsley

Anthriscus sylvestris · also called Cow Parsley, Wild Chervil · flowering

Anthriscus sylvestris is a robust biennial or short-lived perennial native to Europe, western Asia, and northwestern Africa, and one of the most familiar hedgerow and woodland-edge wildflowers in the British Isles. It produces finely divided, fern-like foliage and large flat-topped umbels of tiny white flowers from April to June. The most important care fact is that it self-seeds prolifically and can quickly colonise an area; deadhead before seed sets if spread is unwanted. The plant contains furocoumarins that cause phototoxic skin reactions and is considered mildly to moderately harmful if ingested by cats or dogs.

Growth habit: Basal rosette-forming biennial or short-lived perennial; hollow, ridged stems rise in the second year carrying the umbel inflorescences before dying back.

What fertiliser cow parsley actually wants — and why

Cow Parsley 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 cow parsley: 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 cow parsley, 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 cow parsley:

Generally requires no supplementary feeding in fertile garden soil; a light topdressing of balanced slow-release fertiliser in spring benefits plants on poorer soils. 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 cow parsley 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 cow parsley

Half strength is the safe default for cow parsley — 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 cow parsley first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the cow parsley watering schedule.

Signs you are over-feeding cow parsley

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for cow parsley:

Signs you are under-feeding cow parsley

If the symptoms point at watering, light or roots rather than nutrition, the full cow parsley care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush the pot of cow parsley 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 cow parsley

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 cow parsley — frequently asked questions

What fertiliser does cow parsley 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. Cow Parsley 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 cow parsley?

Generally requires no supplementary feeding in fertile garden soil; a light topdressing of balanced slow-release fertiliser in spring benefits plants on poorer soils. Generally requires no supplementary feeding in fertile garden soil; a light topdressing of balanced slow-release fertiliser in spring benefits plants on poorer soils. 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 cow parsley?

Half strength is the safe default for cow parsley — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

What does over-feeding cow parsley 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 cow parsley 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 cow parsley?

Flush the pot of cow parsley 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.

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