Fertilising guide
How to fertilise Small-flowered alumroot (Heuchera micrantha)— schedule & NPK
Also called Small-flowered alumroot, Crevice alumroot, Small alumroot.
More about small-flowered alumroot
About Small-flowered alumroot
Heuchera micrantha · also called Small-flowered alumroot, Crevice alumroot · flowering
Small-flowered alumroot is a Pacific coast evergreen perennial native to moist, rocky cliffs and woodland slopes from British Columbia to California. It produces elegant wiry stems carrying tiny white to cream flowers over a long summer season above attractively lobed, often silver-veined, green to bronze foliage. This species is a key parent of many popular foliage Heuchera cultivars, including 'Palace Purple'.
Growth habit: Mound-forming, evergreen to semi-evergreen perennial with kidney-shaped to shallowly lobed leaves, often with silver or pale veining; very slender, branching flower scapes carry open panicles of tiny flowers
Watch for — Vine weevil: Vine weevil larvae (white C-shaped grubs) feed on Heuchera roots, causing sudden collapse. Apply parasitic nematodes (Steinernema kraussei) in late summer/autumn as a soil drench to container and border plants. Inspect roots during division.
What fertiliser small-flowered alumroot actually wants — and why
Small-flowered alumroot 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 small-flowered alumroot: 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 small-flowered alumroot, 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 small-flowered alumroot:
Apply a balanced slow-release fertiliser in early spring. Supplement with a liquid balanced feed monthly during the flowering season. Leaf mould topdressing in autumn feeds the plant naturally and helps protect the crown. Avoid excessive nitrogen. Treat that as monthly 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 small-flowered alumroot 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 small-flowered alumroot
Half strength is the safe default for small-flowered alumroot — 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 small-flowered alumroot first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the small-flowered alumroot watering schedule.
Signs you are over-feeding small-flowered alumroot
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for small-flowered alumroot:
- 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 small-flowered alumroot
- 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 small-flowered alumroot care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of small-flowered alumroot 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 small-flowered alumroot
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 small-flowered alumroot — frequently asked questions
What fertiliser does small-flowered alumroot 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. Small-flowered alumroot 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 small-flowered alumroot?
Apply a balanced slow-release fertiliser in early spring. Supplement with a liquid balanced feed monthly during the flowering season. Leaf mould topdressing in autumn feeds the plant naturally and helps protect the crown. Avoid excessive nitrogen. Apply a balanced slow-release fertiliser in early spring. Supplement with a liquid balanced feed monthly during the flowering season. Leaf mould topdressing in autumn feeds the plant naturally and helps protect the crown. Avoid excessive nitrogen. Treat that as monthly 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 small-flowered alumroot?
Half strength is the safe default for small-flowered alumroot — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding small-flowered alumroot 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 small-flowered alumroot 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 small-flowered alumroot?
Flush the pot of small-flowered alumroot 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
- Small-flowered alumroot care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water small-flowered alumroot — 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 douglas fir
- How to fertilise deodar cedar
- How to fertilise atlas cedar
- All 6887 fertilising guides in the Growli library