Cold hardiness & minimum temperature

Is Spike Moss (Selaginella apoda)cold hardy? Hardiness zone & min temp

Also called Meadow Spikemoss, Creeping Selaginella.

More about spike moss

About Spike Moss

Selaginella apoda · also called Meadow Spikemoss, Creeping Selaginella · houseplant

Selaginella apoda is a low-growing, mat-forming spikemoss native to eastern North America, with delicate bright-green scale-like leaves. It thrives in moist, shaded terrariums or humid windowsills. Not a true moss or fern, but similarly considered non-toxic, with no ASPCA listings indicating harm.

Cold limit: USDA 5-9 (outdoor ground cover in frost-tolerant zones) · RHS H4 (15-24°C)

What spike moss's hardiness rating actually means

Yes — spike moss is genuinely cold hardy. Rated RHS H4 and USDA 5-9 (outdoor ground cover in frost-tolerant zones), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 5-9 (outdoor ground cover in frost-tolerant zones) — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about −10 to −5 °C. Spike Moss is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for spike moss as it gets too cold:

It tolerates winter lows to about −10 to −5 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can spike moss go outside or overwinter — and where?

Plant it out within USDA 5-9 (outdoor ground cover in frost-tolerant zones) and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when spike moss can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Spike Moss hardiness — frequently asked questions

Is spike moss cold hardy?

Yes — spike moss is genuinely cold hardy. Rated RHS H4 and USDA 5-9 (outdoor ground cover in frost-tolerant zones), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Spike Moss is hardy across USDA 5-9 (outdoor ground cover in frost-tolerant zones); it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature spike moss can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Spike Moss is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is spike moss?

Spike Moss is rated USDA 5-9 (outdoor ground cover in frost-tolerant zones) and RHS H4 — Hardy in an average winter across much of the temperate world.

Can spike moss survive winter outside?

Plant it out within USDA 5-9 (outdoor ground cover in frost-tolerant zones) and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to spike moss below its minimum temperature?

It tolerates winter lows to about −10 to −5 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.