Growing Carpeting (Foreground) Plants in a Planted Tank
A practical guide to growing a low foreground carpet: light and CO2 needs, the best species by difficulty, planting technique, spread via runners, trimming and low-tech options.
A carpet is a low foreground planting that spreads horizontally across the substrate, emulating a lawn of grass or moss. Carpets are central to styles such as the Nature Aquarium, where small-leaved plants like Glossostigma elatinoides, Eleocharis acicularis and Eleocharis parvula are used to cover the foreground. Growing one densely and keeping it compact, rather than letting it grow tall and leggy, is the main challenge.
Light, CO2 and substrate
Most carpets demand strong light, stable CO2 and a nutrient-rich substrate to stay low and dense. With CO2, many carpets thrive at modest light: dwarf hairgrass spreads well at just 40 to 50 umol of PAR at the substrate as long as CO2 is reasonable (around 20 ppm or more). Without injected CO2, the same plant needs far more light, around 100 umol of PAR, to grow. A rich aquasoil supports better rooting and lets some demanding carpets grow without saturating the water column with fertiliser.
Choosing a carpet by difficulty
| Plant | Difficulty | Notes |
|---|---|---|
| Monte Carlo (Micranthemum) | Easy / hardy | Grows on wood or rock without substrate; can carpet without CO2 given enough light and time |
| Dwarf hairgrass (Eleocharis) | Moderate | Spreads by runners; feeds well from the substrate |
| Staurogyne repens | Easy | Low-growing; grows much better with rich soil substrate |
| Marsilea / Dwarf sagittaria | Low-tech friendly | Tolerate no-CO2 setups but grow slowly |
| HC Cuba (Hemianthus callitrichoides) | Hard / picky | Smallest leaves; needs high CO2 and soil; deteriorates quickly if overcrowded |
Monte Carlo and HC Cuba look similar but differ greatly in care: MC is hardy and tolerates overcrowding, whereas HC has the smallest oval leaves of the carpets and is extremely picky, needing high CO2 and soil to do well.
Planting technique
- Split the plant into the smallest portions you can manage; for hairgrass this can be clusters of fewer than ten blades.
- Use tweezers to push each portion firmly into the substrate.
- Space portions roughly 2 to 4 cm apart so they have room to spread and fill in evenly.
- Keep light, CO2 and nutrients stable while the carpet establishes.
Planting in small clusters lets individual plants root properly, which in turn lets the carpet grow and spread faster and more evenly than planting large dense clumps.
Spread, trimming and patience
Carpets are typically short plants that spread across the soil surface using runners, sending out horizontal shoots that root and form new plants. Regular trimming keeps the carpet compact and encourages horizontal, rather than vertical, growth. Establishing a carpet takes time: a dwarf hairgrass carpet grown from scratch in a small low-tech tank took around three months to fill in.
Melt and transition
Newly purchased plants are often grown emersed, so they must transition to submersed conditions, which is the most difficult stage of establishing a carpet. Adequate CO2 greatly speeds acclimatisation, and dosing a comprehensive fertiliser from the start supports under-developed roots. Some early melt of the original emersed leaves is normal as new submersed growth takes over.