Fertilising guide
How to fertilise wavy hair grass (Deschampsia flexuosa)— schedule & NPK
Also called wavy hair grass, crinkled hair grass.
More about wavy hair grass
About wavy hair grass
Deschampsia flexuosa · also called wavy hair grass, crinkled hair grass · flowering
Wavy hair grass is a delicate, wiry cool-season perennial grass of acid heathlands, moorlands, and open woodlands in Europe and North America. Its slender, hair-fine leaves form low, dark-green tussocks from which airy, wavy-stemmed panicles of tiny, glistening spikelets rise in early summer. Ideal for acid soils, heath gardens, and naturalised moorland settings with striking translucent flower clouds.
Growth habit: Dense, tufted, clump-forming cool-season semi-evergreen grass; low, wiry basal mound with tall, slender, wavy flowering stems rising well above the foliage.
What fertiliser wavy hair grass actually wants — and why
wavy hair 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 wavy hair 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 wavy hair 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 wavy hair grass:
Do not fertilise; this grass naturally grows in nutrient-poor conditions and feeding encourages rank, floppy growth and can kill it in rich soils. No amendments other than acid mulch (pine bark) are recommended. 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 wavy hair 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 wavy hair grass
Half strength is the safe default for wavy hair 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 wavy hair grass first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the wavy hair grass watering schedule.
Signs you are over-feeding wavy hair grass
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for wavy hair 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 wavy hair 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 wavy hair grass care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of wavy hair 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 wavy hair 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 wavy hair grass — frequently asked questions
What fertiliser does wavy hair 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. wavy hair 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 wavy hair grass?
Do not fertilise; this grass naturally grows in nutrient-poor conditions and feeding encourages rank, floppy growth and can kill it in rich soils. No amendments other than acid mulch (pine bark) are recommended. Do not fertilise; this grass naturally grows in nutrient-poor conditions and feeding encourages rank, floppy growth and can kill it in rich soils. No amendments other than acid mulch (pine bark) are recommended. 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 wavy hair grass?
Half strength is the safe default for wavy hair grass — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding wavy hair 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 wavy hair 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 wavy hair grass?
Flush the pot of wavy hair 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
- wavy hair grass care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water wavy hair 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 utricularia sandersonii
- How to fertilise aeschynanthus radicans 'curly q'
- How to fertilise tuberous begonia
- All 6887 fertilising guides in the Growli library