Fertilising guide
How to fertilise Sempervivum 'Killer' (Sempervivum 'Killer')— schedule & NPK
Also called Killer hens and chicks.
More about sempervivum 'killer'
About Sempervivum 'Killer'
Sempervivum 'Killer' · also called Killer hens and chicks · houseplant
Sempervivum 'Killer' is a vivid hybrid houseleek whose rosettes turn intense red to scarlet in strong sun and cool weather, mellowing to green-bronze in heat or shade. Compact, cold-hardy, and drought-tolerant, it offsets freely into bright colonies. Grown for its dramatic red flush, it needs full sun, gritty fast-draining soil, and a strict soak-and-dry routine.
Growth habit: Evergreen, mat-forming succulent. Rosettes multiply by stoloniferous offsets around a central plant to form spreading colonies. Each rosette is monocarpic, flowering once before dying and being replaced by its chicks.
Watch for — Loss of red colour: The scarlet flush depends on full sun, cool temperatures, and lean conditions. In heat, shade, or with feeding the rosettes green over; raise light, reduce fertiliser, and expect summer warmth to soften the colour.
What fertiliser sempervivum 'killer' actually wants — and why
Sempervivum 'Killer' is a light-feeding succulent — a gentle, low-nitrogen feed a few times in growth keeps it plump without forcing the weak, stretched growth over-feeding causes.
A cactus and succulent formula or a diluted balanced feed with modest, even numbers. Avoid high-nitrogen plant foods — they make a succulent etiolate and grow soft, fracture-prone tissue.
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 sempervivum 'killer': 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 sempervivum 'killer', 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 sempervivum 'killer':
Minimal. One dilute low-nitrogen succulent feed in late spring is enough. Rich feeding pushes soft green growth and suppresses the red colour the cultivar is prized for, so keep nutrients lean. Keep that to sparingly through the growing season between spring through early autumn (roughly March to September) and stop entirely once growth slows for winter.
The dormant-season rule matters more than the exact interval: skip feeding entirely when sempervivum 'killer' 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 sempervivum 'killer'
Quarter to half strength at most for sempervivum 'killer'. Succulents take up very little, and a strong dose burns the fine roots before the plant can use it.
Feeding always goes onto already-damp soil, never dry roots — water sempervivum 'killer' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the sempervivum 'killer' watering schedule.
Signs you are over-feeding sempervivum 'killer'
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for sempervivum 'killer':
- Stretched, leggy, pale growth with widely spaced leaves.
- A white salt crust on the soil or around the pot rim.
- Brown, crisped leaf tips and edges.
- Soft, mushy tissue at the base — over-feeding plus damp soil rots it.
Signs you are under-feeding sempervivum 'killer'
- Uncommon — succulents tolerate lean conditions well.
- Very slow growth and dull, faded colour over a long period.
- Older leaves shed faster than new ones replace them in a tired old mix.
If the symptoms point at watering, light or roots rather than nutrition, the full sempervivum 'killer' care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Feed lightly enough and you rarely need to flush, but once a year run plain water through the pot of sempervivum 'killer' until it drains clear, and refresh the gritty mix every 2-3 years.
Organic vs synthetic feeds for sempervivum 'killer'
Organic options
A heavily diluted seaweed or worm-casting feed once or twice in summer. UK: a drop of Westland seaweed feed; US: quarter-strength Espoma Cactus! or Dr. Earth liquid. Fresh free-draining mix matters more than any feed.
Synthetic / liquid feeds
A dedicated cactus/succulent liquid at quarter to half strength — UK: Baby Bio Cacti & Succulent Drip Feeders or Westland; US: Miracle-Gro Succulent Plant Food or Schultz Cactus Plus.
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 sempervivum 'killer' — frequently asked questions
What fertiliser does sempervivum 'killer' need?
A cactus and succulent formula or a diluted balanced feed with modest, even numbers. Avoid high-nitrogen plant foods — they make a succulent etiolate and grow soft, fracture-prone tissue. Sempervivum 'Killer' is a light-feeding succulent — a gentle, low-nitrogen feed a few times in growth keeps it plump without forcing the weak, stretched growth over-feeding causes.
How often should I feed sempervivum 'killer'?
Minimal. One dilute low-nitrogen succulent feed in late spring is enough. Rich feeding pushes soft green growth and suppresses the red colour the cultivar is prized for, so keep nutrients lean. Minimal. One dilute low-nitrogen succulent feed in late spring is enough. Rich feeding pushes soft green growth and suppresses the red colour the cultivar is prized for, so keep nutrients lean. Keep that to sparingly through the growing season between spring through early autumn (roughly March to September) and stop entirely once growth slows for winter.
What strength of feed for sempervivum 'killer'?
Quarter to half strength at most for sempervivum 'killer'. Succulents take up very little, and a strong dose burns the fine roots before the plant can use it.
What does over-feeding sempervivum 'killer' look like?
Stretched, leggy, pale growth with widely spaced leaves. A white salt crust on the soil or around the pot rim. Brown, crisped leaf tips and edges. Soft, mushy tissue at the base — over-feeding plus damp soil rots it. Feeding sempervivum 'killer' like a leafy houseplant is the classic error — it produces a flush of pale, stretched, floppy growth that never firms up and is prone to rot at the base.
Should I flush the soil of sempervivum 'killer'?
Feed lightly enough and you rarely need to flush, but once a year run plain water through the pot of sempervivum 'killer' until it drains clear, and refresh the gritty mix every 2-3 years.
Keep reading
- Sempervivum 'Killer' care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water sempervivum 'killer' — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise snake plant
- How to fertilise dracaena
- How to fertilise peperomia
- All 2464 fertilising guides in the Growli library