Spreading Spike Moss (Krauss's Spike Moss) care

Light

The Goldilocks zone. Not the south-facing windowsill (too hot, too direct), not the back of the room (too dim, growth stalls). Prefers medium to bright indirect light. Tolerates lower light levels but growth becomes sparse and pale. Avoid direct sun which quickly scorches the delicate foliage. A north- or east-facing windowsill is ideal. If you can't decide, a free phone lux-meter app aimed at the leaf at noon should read between 800 and 1,500 lux.

Watering

Watering spreading spike moss: keep soil consistently moist; check every 2-3 days. 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. Selaginella kraussiana requires constant moisture and will rapidly wilt and brown if allowed to dry out. Water gently but frequently, keeping the growing medium just moist. Avoid puddling water on the foliage to reduce disease risk.

Soil and pot

Spreading Spike Moss grows best in moisture-retentive, peat-free mix high in organic matter. Use a mix of fine coco coir, leaf mould, and a little perlite. The mix should hold moisture while still allowing some air to the roots. Slightly acidic pH (5.5-6.5) is optimal. 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

Spreading Spike Moss sits happiest at around 70-90% humidity and 10-24°C (50-75°F). High humidity is essential. This plant thrives in terrariums and closed-case environments where humidity can be kept very high. In open rooms, daily misting and a pebble tray are the minimum requirements. If you keep the room above 10 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 spreading spike moss sparingly. Feed with a very dilute balanced liquid fertiliser at quarter strength once a month during the growing season. Over-fertilising will cause lush but weak, disease-prone growth. 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 spreading spike moss in the Growli community. Each is annotated with the most common cause so you know where to start.

• Browning and desiccation — The most common problem — caused by low humidity or drying out. Restore moisture promptly and increase ambient humidity.
• Legginess — Insufficient light leads to sparse, stretched growth. Move to a brighter indirect-light position.
• Root rot — While it needs constant moisture, waterlogged soil causes rot. Ensure the growing medium is moist but well-aerated, not sodden.
• Fungus gnats — Common in perpetually moist conditions. Allow the surface to just dry slightly between waterings and use yellow sticky traps.
• Invasive spreading outdoors — In warm, moist climates this species can become weedy. In the garden, contain it to defined beds or use in enclosed pots.

Companion plants

Spreading Spike Moss pairs well with Fittonia albivenis, Peperomia rotundifolia, Blechnum fluviatile, and Pilea glauca. 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

Very easily propagated by stem cuttings. Take 5-8 cm sections, remove the lower leaves, and press into moist compost or lay flat on the substrate surface. Roots form rapidly in high humidity, usually within 2-3 weeks. 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

Spreading Spike Moss is pet-safe. Not individually listed by the ASPCA. Selaginella (spike mosses) are not true ferns or flowering plants, but are broadly considered non-toxic to cats and dogs and do not belong to any toxic plant family. 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.

Spreading Spike Moss deep-dive guides

Every aspect of spreading spike moss care, each with its own calibrated guide:

• Common spreading spike moss problems & fixes
• Spreading Spike Moss watering schedule
• Spreading Spike Moss light requirements
• Best soil mix for spreading spike moss
• Spreading Spike Moss fertilizing guide
• When to repot spreading spike moss
• How to propagate spreading spike moss
• How to prune spreading spike moss
• What's eating my spreading spike moss?
• Spreading Spike Moss growth rate & size
• Spreading Spike Moss cold hardiness
• Spreading Spike Moss temperature & humidity
• Is spreading spike moss toxic to cats & dogs?
• Is spreading spike moss toxic to cats?
• Is spreading spike moss toxic to dogs?
• All 11 Selaginella varieties

Featured in these plant shortlists

Spreading Spike Moss qualifies for 18 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 low-light houseplants — Houseplants that need no direct sun and cope with a north-facing room or a spot well back from a window.
• 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 pet-safe low-light plants — Non-toxic to cats and dogs AND happy with no direct sun — the two hardest constraints to satisfy at once.
• Best plants for cold, dark rooms — Houseplants that cope with BOTH low light and a cool, unheated room — the hardest indoor spot to fill. Every pick tolerates a low of about 10°C and shade.
• Best drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best houseplants for beginners — Forgiving of irregular light and watering — the houseplants least likely to die in a new plant parent’s first season.
• Best humidity-loving houseplants — Houseplants that thrive in a bathroom, kitchen, or by a humidifier — selected by documented humidity preference.
• Best bathroom plants — Humidity-loving houseplants that also cope with lower light — suited to the steamy, often-dim conditions of a typical bathroom.
• Best pet-safe low-maintenance plants — Non-toxic to cats and dogs and forgiving of forgotten watering — the easiest safe choices for a busy pet household.
• Best pet-safe bathroom plants — Non-toxic to cats and dogs and happy in the humid, lower-light conditions of a bathroom — safe greenery for the smallest room.
• Best small & tabletop houseplants — Compact houseplants that stay under about 40 cm — desk, shelf and windowsill plants that never outgrow a small space.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Best fast-growing houseplants — Houseplants documented as fast or vigorous growers — quick to fill a pot, cover a pole or trail down a shelf.
• Best pet-safe bedroom plants — Non-toxic to cats and dogs and happy in lower light — calming greenery for a bedroom where a pet often sleeps too.
• 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

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Spreading Spike Moss is also known as Krauss's Spike Moss, Mat Spikemoss, and Trailing Spike Moss.

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