Fertilising guide
How to fertilise Andean Silver-Leaf Sage (Salvia discolor)— schedule & NPK
Also called Andean Silver-Leaf Sage, Peruvian Black Sage, Concolor Sage, Andean Sage.
More about andean silver-leaf sage
About Andean Silver-Leaf Sage
Salvia discolor · also called Andean Silver-Leaf Sage, Peruvian Black Sage · flowering
Salvia discolor is a striking tender perennial native to Peru, prized for its combination of silvery-white woolly undersides on aromatic leaves (which smell faintly of blackcurrant) and almost-black, deep indigo-purple flowers appearing from September to November. It is frost-tender (RHS H2) and must be overwintered under glass in the UK and most of the US; in warm climates (USDA zones 9b–10b) it may be grown outdoors year-round. The single most important care point is sharp drainage — root rot in wet or cold conditions is the primary cause of loss. The Salvia genus is considered non-toxic to cats and dogs by the ASPCA, though mild stomach upset from ingestion is possible.
Growth habit: Sprawling, semi-upright sub-shrubby perennial with lax, arching stems; tends to flop outward as it matures, making it well-suited to hanging baskets and raised containers.
What fertiliser andean silver-leaf sage actually wants — and why
Andean Silver-Leaf Sage 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 andean silver-leaf sage: 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 andean silver-leaf sage, 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 andean silver-leaf sage:
Feed fortnightly with a balanced liquid fertiliser during spring and summer; switch to a low-nitrogen, high-potassium feed in late summer to encourage flowering rather than foliage growth. 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 andean silver-leaf sage 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 andean silver-leaf sage
Half strength is the safe default for andean silver-leaf sage — 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 andean silver-leaf sage first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the andean silver-leaf sage watering schedule.
Signs you are over-feeding andean silver-leaf sage
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for andean silver-leaf sage:
- 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 andean silver-leaf sage
- 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 andean silver-leaf sage care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of andean silver-leaf sage 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 andean silver-leaf sage
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 andean silver-leaf sage — frequently asked questions
What fertiliser does andean silver-leaf sage 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. Andean Silver-Leaf Sage 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 andean silver-leaf sage?
Feed fortnightly with a balanced liquid fertiliser during spring and summer; switch to a low-nitrogen, high-potassium feed in late summer to encourage flowering rather than foliage growth. Feed fortnightly with a balanced liquid fertiliser during spring and summer; switch to a low-nitrogen, high-potassium feed in late summer to encourage flowering rather than foliage growth. 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 andean silver-leaf sage?
Half strength is the safe default for andean silver-leaf sage — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding andean silver-leaf sage 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 andean silver-leaf sage 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 andean silver-leaf sage?
Flush the pot of andean silver-leaf sage 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
- Andean Silver-Leaf Sage care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water andean silver-leaf sage — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
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- All 10153 fertilising guides in the Growli library