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Plant care

Brazilian Micro Sword (Micro Sword) care

Lilaeopsis brasiliensis

Also called Micro Sword, Carpet Grass, Brazilian Micro Sword Plant.

RHS H1cUSDA 9–12Pet-safeIndoor 4–8 cm tall

Watering rhythm

Bright indirect light (just back from a sunny window)

Permanently submerged aquatic plant

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Light

Bright indirect light (just back from a sunny window)

Soil

Fine nutrient-rich aquasoil or sandy substrate

Humidity

Aquatic — 80–95% for emersed or paludarium cultivation

Temp

20–28°C

Pet safety

Pet-safe

Mature size

4–8 cm tall

Care at a glance

Light

Bright but filtered. Brazilian Micro Sword burns within days in unfiltered south-facing summer sun, and stops growing within months in deep shade. Requires moderate to high aquarium lighting (40–80 PAR at substrate level) for dense carpeting. In low light it survives but grows sparsely and slowly without forming a tight carpet. CO2 injection greatly improves carpet density. If you only have a south window, set the plant back 1.5 m or hang a sheer curtain — both knock the intensity down into the right range.

Watering

Watering brazilian micro sword: permanently submerged aquatic plant. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Adaptable water parameters: pH 6.5–7.5, GH 4–18. Tolerates a range of hardness levels. CO2 injection accelerates runner spread. Good water circulation prevents algae build-up on the short leaf blades.

Soil and pot

Brazilian Micro Sword grows best in fine nutrient-rich aquasoil or sandy substrate. Plant small portions of the runners 1–2 cm apart into fine substrate, burying the thin roots but not the leaf blades. Root tabs placed every 10 cm encourage vigorous runner production. Substrate depth of 4–6 cm is adequate. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Brazilian Micro Sword sits happiest at around Aquatic — 80–95% for emersed or paludarium cultivation humidity and 20–28°C (68–82°F). Can be grown emersed in a very humid paludarium or bog garden. The emergent form has slightly wider leaf blades and is more robust once acclimated. If you keep the room above 20–28°C year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed brazilian micro sword sparingly. Apply a balanced liquid fertiliser weekly. Root tabs placed at regular intervals in the substrate are particularly beneficial because the plant feeds heavily from the roots. Potassium and iron help maintain bright green colour. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on brazilian micro sword in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Sparse, non-carpeting growth — Low light is the most common cause. Ensure PAR at substrate exceeds 40 and consider adding CO2 injection to stimulate runner production.
  • Algae on leaf blades — Short blades can be quickly smothered by green spot algae. Add nerite snails and Otocinclus catfish; maintain stable CO2 and lighting duration.
  • Melting after planting — Tissue-cultured or emersed plants commonly melt when first submerged. New submersed leaves will grow within 2–3 weeks; remove dead material.
  • Slow runner spread — Without CO2 injection and adequate light, runner spread is very slow. Address these two factors first before assuming substrate or fertiliser issues.
  • Competition from other plants — Faster-growing mid-ground plants can shade out the low carpet. Maintain regular trimming of surrounding plants to protect light access.

Companion plants

Brazilian Micro Sword pairs well with Hemianthus callitrichoides, Marsilea crenata, and Glossostigma elatinoides. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Naturally spreads by creeping rhizomatous runners. Accelerate propagation by dividing established mats into small plugs and replanting across bare substrate sections. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Brazilian Micro Sword is pet-safe. Lilaeopsis brasiliensis (Apiaceae) is not listed by the ASPCA as toxic to cats, dogs, or horses. No toxic compounds are documented in this aquatic species; considered pet-safe. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Brazilian Micro Sword care — frequently asked questions

What is the common name for Lilaeopsis brasiliensis?

Lilaeopsis brasiliensis is most commonly called Brazilian Micro Sword, but it is also known as Micro Sword, Carpet Grass, Brazilian Micro Sword Plant. The names refer to the same species, so care instructions for Brazilian Micro Sword apply identically to anything sold as Micro Sword.

How much light does brazilian micro sword need?

Brazilian Micro Sword grows best in bright indirect light (just back from a sunny window). Requires moderate to high aquarium lighting (40–80 PAR at substrate level) for dense carpeting. In low light it survives but grows sparsely and slowly without forming a tight carpet. CO2 injection greatly improves carpet density.

How often should I water brazilian micro sword?

Water brazilian micro sword permanently submerged aquatic plant. Adaptable water parameters: pH 6.5–7.5, GH 4–18. Tolerates a range of hardness levels. CO2 injection accelerates runner spread. Good water circulation prevents algae build-up on the short leaf blades. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is brazilian micro sword toxic to cats and dogs?

Brazilian Micro Sword is pet-safe. Lilaeopsis brasiliensis (Apiaceae) is not listed by the ASPCA as toxic to cats, dogs, or horses. No toxic compounds are documented in this aquatic species; considered pet-safe.

What USDA hardiness zone does brazilian micro sword grow in?

Brazilian Micro Sword is rated for USDA zone 9–12 (can grow in outdoor bog or shallow pond edges in warm climates) and RHS hardiness H1c. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Brazilian Micro Sword deep-dive guides

Every aspect of brazilian micro sword care, each with its own calibrated guide:

Featured in these plant shortlists

Brazilian Micro Sword qualifies for 8 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

  • Best pet-safe houseplants — Houseplants the ASPCA lists as non-toxic to cats and dogs — every one verified against the ASPCA toxic and non-toxic plant list.
  • Best plants for a north-facing window — Houseplants for a north-facing window: bright, even, indirect light and no scorching direct sun. Each pick verified against its documented light needs.
  • Best humidity-loving houseplants — Houseplants that thrive in a bathroom, kitchen, or by a humidifier — selected by documented humidity preference.
  • Best pet-safe plants for bright light — Non-toxic to cats and dogs and happy in a bright, sunny spot — safe plants for your best-lit windowsill.
  • Best small & tabletop houseplants — Compact houseplants that stay under about 40 cm — desk, shelf and windowsill plants that never outgrow a small space.
  • Best cat-safe plants — Houseplants the ASPCA lists as non-toxic to cats (and dogs) — safe greenery for a home with a curious cat.
  • Best dog-safe plants — Houseplants the ASPCA lists as non-toxic to dogs (and cats) — safe greenery for a home with a curious dog.
  • Best small pet-safe plants — Compact, tabletop houseplants that are also ASPCA non-toxic to cats and dogs — safe greenery for a desk or shelf.
  • Browse all 30 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Brazilian Micro Sword is also known as Micro Sword, Carpet Grass, and Brazilian Micro Sword Plant.