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Fertilising guide

How to fertilise Spike Moss (Selaginella apoda)— schedule & NPK

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.

Growth habit: Low-growing creeping mat-former

Watch for — Pale or yellowing growth: Usually caused by excessive light or low nutrients. Move to a shadier spot and apply a dilute feed.

What fertiliser spike moss actually wants — and why

Spike Moss is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.

A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula.

For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for spike moss: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.

How often to feed spike moss, and which months

Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For spike moss:

Apply a very dilute balanced liquid fertiliser (quarter strength) once a month during spring and summer. Selaginella has low nutrient requirements and is sensitive to over-fertilisation. Treat that as once a month between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.

The dormant-season rule matters more than the exact interval: skip feeding entirely when spike moss is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.

What strength to mix for spike moss

Half strength is the safe default for spike moss — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

Feeding always goes onto already-damp soil, never dry roots — water spike moss first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the spike moss watering schedule.

Signs you are over-feeding spike moss

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for spike moss:

Signs you are under-feeding spike moss

If the symptoms point at watering, light or roots rather than nutrition, the full spike moss care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush the pot of spike moss with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.

Organic vs synthetic feeds for spike moss

Organic options

A diluted seaweed or worm-casting feed, or fish emulsion if you can tolerate the smell indoors. UK: Westland or Baby Bio Organic, dilute seaweed; US: Espoma Indoor! or Neptune's Harvest fish & seaweed. Slow, gentle and hard to overdo.

Synthetic / liquid feeds

A general-purpose houseplant liquid at half strength — UK: Baby Bio, Westland Houseplant Feed or Phostrogen; US: Miracle-Gro Indoor Plant Food or Schultz. Convenient and fast-acting; the only risk is overdoing it.

Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.

Fertilising spike moss — frequently asked questions

What fertiliser does spike moss need?

A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula. Spike Moss is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.

How often should I feed spike moss?

Apply a very dilute balanced liquid fertiliser (quarter strength) once a month during spring and summer. Selaginella has low nutrient requirements and is sensitive to over-fertilisation. Apply a very dilute balanced liquid fertiliser (quarter strength) once a month during spring and summer. Selaginella has low nutrient requirements and is sensitive to over-fertilisation. Treat that as once a month between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.

What strength of feed for spike moss?

Half strength is the safe default for spike moss — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

What does over-feeding spike moss look like?

Brown, crispy leaf tips and edges with no sign of underwatering. A white, crusty salt deposit on the soil surface or pot rim. Weak, pale, stretched new growth that flops. Lower leaves yellow and drop while the soil is correctly watered. Feeding spike moss year-round on a fixed schedule, including dark winter months, is the most common mistake — it cannot use the nutrients in low light and the surplus simply burns the roots and crusts the soil.

Should I flush the soil of spike moss?

Flush the pot of spike moss with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.

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