Growli
Let's go

Fertilising guide

How to fertilise Cobweb Houseleek (Sempervivum arachnoideum)— schedule & NPK

Also called Cobweb Hens and Chicks.

More about cobweb houseleek

About Cobweb Houseleek

Sempervivum arachnoideum · also called Cobweb Hens and Chicks · houseplant

Cobweb Houseleek forms tight rosettes of green-to-red leaves laced with fine white cobweb-like hairs across the tips, a distinctive alpine trait. It clusters into mats of offset 'chicks', tolerates frost and drought, and dies after flowering while leaving offsets behind. Hardy, low-care, and ASPCA non-toxic to cats and dogs.

Growth habit: Monocarpic clustering rosettes; the parent dies after flowering but ever-multiplying offsets ('chicks') keep the colony going indefinitely.

What fertiliser cobweb houseleek actually wants — and why

Cobweb Houseleek 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 cobweb houseleek: 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 cobweb houseleek, 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 cobweb houseleek:

Minimal. Feeding is rarely needed and softens the tight alpine form; at most one weak, dilute feed in spring. Lean conditions give the best colour and webbing. Treat that as sparingly through the growing season 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 cobweb houseleek 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 cobweb houseleek

Half strength is the safe default for cobweb houseleek — 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 cobweb houseleek first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the cobweb houseleek watering schedule.

Signs you are over-feeding cobweb houseleek

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

Signs you are under-feeding cobweb houseleek

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

Flushing and leaching the salts

Flush the pot of cobweb houseleek 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 cobweb houseleek

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 cobweb houseleek — frequently asked questions

What fertiliser does cobweb houseleek 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. Cobweb Houseleek 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 cobweb houseleek?

Minimal. Feeding is rarely needed and softens the tight alpine form; at most one weak, dilute feed in spring. Lean conditions give the best colour and webbing. Minimal. Feeding is rarely needed and softens the tight alpine form; at most one weak, dilute feed in spring. Lean conditions give the best colour and webbing. Treat that as sparingly through the growing season 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 cobweb houseleek?

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

What does over-feeding cobweb houseleek 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 cobweb houseleek 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 cobweb houseleek?

Flush the pot of cobweb houseleek 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.

Keep reading