Dwarf Hairgrass
Dwarf hairgrass is the go-to carpeting plant - fine green blades that, given enough light, spread by runners into a lawn across the foreground.
🗓️ Last reviewed: July 2026
Overview
Dwarf hairgrass is the go-to carpeting plant - fine green blades that, given enough light, spread by runners into a lawn across the foreground. That 'given enough light' is the catch: a dense carpet really wants strong light and usually CO2, which pushes it out of true beginner territory. (Eleocharis parvula/acicularis.)
Origin & Natural Habitat
Shallow margins of ponds, lakes and marshes across much of the world.
Appearance
Thin, grass-like green blades a few centimetres tall that knit into a lawn as runners fill in the gaps.
Why People Grow It - Qualities & Benefits
- Creates a true foreground carpet
- Natural, meadow-like aquascape look
- Spreads by runners once established
- Oxygenates and shelters fry
Care
Light: High - the single biggest factor. Low light gives a thin, leggy, algae-prone patch, not a carpet.
Water: 18-26°C, pH 6.0-7.5, soft to moderately hard.
Substrate: Nutrient-rich substrate; plant small tufts a few centimetres apart so runners can fill in.
CO₂ & feeding: Strongly recommended for a dense, healthy carpet; without it, expect slow, patchy results.
Placement: Foreground carpet.
Extra: ⚠️ This is the plant beginners blame themselves for. A thin, browning carpet is almost always not enough light (and no CO2), not a green thumb problem. Match the light and CO2 before buying more.
Propagation
Spreads by runners; you can also trim and replant tufts to speed coverage.
Common Problems & Pests
Thin, leggy growth and algae in low light; slow to fill without CO2. Trim to encourage horizontal spread.
Toxicity & Safety
Non-toxic to livestock; not known to be toxic to cats or dogs.
Best Suited For
- High-tech, CO2-injected tanks
- Aquascapers wanting a lawn
- Bright foregrounds
- Patient carpet growers
FAQ
Why is my hairgrass thin and dying instead of carpeting?
Almost always too little light and no CO2. A dense carpet needs strong light; add CO2 for reliable results. It is not really a low-tech plant.
Do I have to trim it?
Trimming the tops encourages the runners to spread sideways, thickening the carpet faster.