Fertilising guide
How to fertilise Purple Love Grass (Eragrostis spectabilis)— schedule & NPK
Also called purple love grass, tumble grass, petticoat grass.
More about purple love grass
About Purple Love Grass
Eragrostis spectabilis · also called purple love grass, tumble grass · flowering
Purple love grass is a fine-textured native North American ornamental grass prized for its airy, reddish-purple seed cloud in late summer. Extremely drought-tolerant once established, it thrives in poor, sandy soils and full sun. The seed heads detach in autumn and tumble like tumbleweed, dispersing seed naturally across the landscape.
Growth habit: Clump-forming, warm-season ornamental grass with arching, fine-textured foliage and a wide-spreading, cloud-like panicle in late summer
Watch for — Flopping / lax stems: Caused by excessive soil fertility, shade, or supplemental irrigation. Grow in lean, sunny, dry conditions to maintain compact, upright form.
What fertiliser purple love grass actually wants — and why
Purple Love Grass 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 purple love grass: 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 purple love grass, 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 purple love grass:
Avoid fertilising — supplemental nutrients produce floppy, overly lush growth and reduce the ornamental seed-head display. If growth is very poor in extremely depleted soil, a single light application of balanced slow-release granules in spring is the maximum. 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 purple love grass 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 purple love grass
Half strength is the safe default for purple love grass — 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 purple love grass first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the purple love grass watering schedule.
Signs you are over-feeding purple love grass
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for purple love grass:
- 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 purple love grass
- 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 purple love grass care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of purple love grass 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 purple love grass
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 purple love grass — frequently asked questions
What fertiliser does purple love grass 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. Purple Love Grass 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 purple love grass?
Avoid fertilising — supplemental nutrients produce floppy, overly lush growth and reduce the ornamental seed-head display. If growth is very poor in extremely depleted soil, a single light application of balanced slow-release granules in spring is the maximum. Avoid fertilising — supplemental nutrients produce floppy, overly lush growth and reduce the ornamental seed-head display. If growth is very poor in extremely depleted soil, a single light application of balanced slow-release granules in spring is the maximum. 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 purple love grass?
Half strength is the safe default for purple love grass — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding purple love grass 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 purple love grass 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 purple love grass?
Flush the pot of purple love grass 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
- Purple Love Grass care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water purple love grass — 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 anemone coronaria 'hollandia'
- How to fertilise freesia 'pink marble'
- How to fertilise freesia 'royal blue'
- All 6887 fertilising guides in the Growli library