Fertilising guide
How to fertilise Lungwort 'Mrs Moon' (Pulmonaria saccharata)— schedule & NPK
Also called Mrs Moon Lungwort, Bethlehem Sage, Jerusalem Cowslip.
More about lungwort 'mrs moon'
About Lungwort 'Mrs Moon'
Pulmonaria saccharata · also called Mrs Moon Lungwort, Bethlehem Sage · flowering
Lungwort 'Mrs Moon' is a classic spring-flowering shade perennial with heavily silver-spotted, semi-evergreen leaves and funnel-shaped flowers that open pink and age to blue-violet. An excellent ground cover for shaded and woodland borders. Prefers moist, humus-rich soil. Pet-safe according to ASPCA.
Growth habit: Clump-forming semi-evergreen perennial
What fertiliser lungwort 'mrs moon' actually wants — and why
Lungwort 'Mrs Moon' 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 lungwort 'mrs moon': 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 lungwort 'mrs moon', 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 lungwort 'mrs moon':
A spring top-dressing of balanced fertiliser or well-rotted compost is usually sufficient. Pulmonaria is not a heavy feeder; avoid nitrogen-rich feeds that promote soft, disease-prone growth at the expense of the distinctive spotted foliage. 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 lungwort 'mrs moon' 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 lungwort 'mrs moon'
Half strength is the safe default for lungwort 'mrs moon' — 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 lungwort 'mrs moon' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the lungwort 'mrs moon' watering schedule.
Signs you are over-feeding lungwort 'mrs moon'
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for lungwort 'mrs moon':
- 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 lungwort 'mrs moon'
- 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 lungwort 'mrs moon' care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of lungwort 'mrs moon' 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 lungwort 'mrs moon'
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 lungwort 'mrs moon' — frequently asked questions
What fertiliser does lungwort 'mrs moon' 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. Lungwort 'Mrs Moon' 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 lungwort 'mrs moon'?
A spring top-dressing of balanced fertiliser or well-rotted compost is usually sufficient. Pulmonaria is not a heavy feeder; avoid nitrogen-rich feeds that promote soft, disease-prone growth at the expense of the distinctive spotted foliage. A spring top-dressing of balanced fertiliser or well-rotted compost is usually sufficient. Pulmonaria is not a heavy feeder; avoid nitrogen-rich feeds that promote soft, disease-prone growth at the expense of the distinctive spotted foliage. 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 lungwort 'mrs moon'?
Half strength is the safe default for lungwort 'mrs moon' — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding lungwort 'mrs moon' 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 lungwort 'mrs moon' 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 lungwort 'mrs moon'?
Flush the pot of lungwort 'mrs moon' 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
- Lungwort 'Mrs Moon' care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water lungwort 'mrs moon' — 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 menyanthes trifoliata
- How to fertilise aponogeton distachyos
- How to fertilise eichhornia crassipes
- All 11687 fertilising guides in the Growli library