Fertilising guide
How to fertilise Caucasian Rock Cress (Arabis caucasica)— schedule & NPK
Also called Caucasian Rock Cress, Wall Cress, Mountain Cress.
More about caucasian rock cress
About Caucasian Rock Cress
Arabis caucasica · also called Caucasian Rock Cress, Wall Cress · flowering
One of the most widely grown spring rock garden plants, Arabis caucasica produces dense mats of grey-green foliage smothered in fragrant white (or pink, in cultivars) flowers from late winter through spring. Vigorous, easy to grow, and highly frost-hardy. Excellent for dry walls, rock gardens, and border fronts. Cut back hard after flowering to maintain tidiness.
Growth habit: Vigorous, spreading, mat-forming semi-evergreen perennial
What fertiliser caucasian rock cress actually wants — and why
Caucasian Rock Cress 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 caucasian rock cress: 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 caucasian rock cress, 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 caucasian rock cress:
Light feeding only. A balanced granular fertiliser applied in early spring supports flowering without promoting excessive leafy growth. Plants in poor soils may benefit from an autumn feed. Avoid high-nitrogen formulations. 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 caucasian rock cress 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 caucasian rock cress
Half strength is the safe default for caucasian rock cress — 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 caucasian rock cress first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the caucasian rock cress watering schedule.
Signs you are over-feeding caucasian rock cress
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for caucasian rock cress:
- 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 caucasian rock cress
- 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 caucasian rock cress care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of caucasian rock cress 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 caucasian rock cress
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 caucasian rock cress — frequently asked questions
What fertiliser does caucasian rock cress 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. Caucasian Rock Cress 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 caucasian rock cress?
Light feeding only. A balanced granular fertiliser applied in early spring supports flowering without promoting excessive leafy growth. Plants in poor soils may benefit from an autumn feed. Avoid high-nitrogen formulations. Light feeding only. A balanced granular fertiliser applied in early spring supports flowering without promoting excessive leafy growth. Plants in poor soils may benefit from an autumn feed. Avoid high-nitrogen formulations. 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 caucasian rock cress?
Half strength is the safe default for caucasian rock cress — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding caucasian rock cress 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 caucasian rock cress 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 caucasian rock cress?
Flush the pot of caucasian rock cress 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
- Caucasian Rock Cress care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water caucasian rock cress — 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 pyracantha angustifolia
- How to fertilise crabapple 'hanagasa'
- How to fertilise wild crabapple bonsai
- All 8452 fertilising guides in the Growli library