Fertilising guide
How to fertilise Common Ice Plant (Mesembryanthemum crystallinum)— schedule & NPK
Also called Common ice plant, Crystalline ice plant, Iceplant.
More about common ice plant
About Common Ice Plant
Mesembryanthemum crystallinum · also called Common ice plant, Crystalline ice plant · edible
Mesembryanthemum crystallinum is an annual or biennial native to the Mediterranean, Middle East, and southern Africa, naturalised along coastal areas worldwide. Its leaves and stems are covered with large glistening vesicles that resemble ice crystals and have a pleasantly salty, succulent taste, making the plant a valued edible green in coastal cuisines. It demands full sun, very free-draining soil, and tolerates salt, drought, and coastal spray, but will rot quickly in waterlogged conditions. The ASPCA does not list it as toxic to cats or dogs; it is considered non-toxic, though very high consumption of the foliage could cause mild digestive upset due to oxalate content.
Growth habit: Low-growing, spreading annual or biennial with trailing, branching stems; the succulent glistening foliage is the primary ornamental and edible feature.
What fertiliser common ice plant actually wants — and why
Common Ice Plant feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.
Balanced (even N-P-K) at planting for roots and frame, then switch to a high-potassium ("high-potash") tomato-style feed once the first flowers open — potassium is what sizes and ripens fruit, not nitrogen.
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 common ice plant: 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 common ice plant, 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 common ice plant:
No feeding is needed in poor soils; if growing for leaf harvest, a single application of dilute balanced liquid fertiliser in spring will promote lusher foliage. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).
The dormant-season rule matters more than the exact interval: skip feeding entirely when common ice plant 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 common ice plant
Follow the crop-feed label rate for common ice plant — these are calibrated for hungry vegetables. Consistency through fruiting matters more than strength; erratic feeding causes problems like blossom-end rot.
Feeding always goes onto already-damp soil, never dry roots — water common ice plant first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the common ice plant watering schedule.
Signs you are over-feeding common ice plant
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for common ice plant:
- Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen).
- Lush foliage hiding the crop; soft growth prone to pests and disease.
- Salt crust on the soil and scorched leaf edges in containers.
Signs you are under-feeding common ice plant
- Pale, yellowing lower leaves and stunted growth.
- Small fruit, poor set, and a quickly exhausted plant.
- Blossom-end rot and weak cropping from erratic or insufficient feeding.
If the symptoms point at watering, light or roots rather than nutrition, the full common ice plant care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
In containers, fertiliser salts build up fast — water common ice plant thoroughly so excess drains from the base each time, and flush pots with plain water every few weeks to prevent a damaging salt build-up.
Organic vs synthetic feeds for common ice plant
Organic options
Garden compost or well-rotted manure dug in before planting, plus a liquid comfrey or seaweed feed once fruiting starts. UK: comfrey feed or organic Tomorite; US: Espoma Tomato-tone or Neptune's Harvest. Builds soil and feeds in one.
Synthetic / liquid feeds
A balanced feed at planting then a high-potash tomato feed in fruiting — UK: Growmore at planting then Tomorite (Levington) or Phostrogen; US: a balanced 10-10-10 then Miracle-Gro Tomato or a bloom booster.
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 common ice plant — frequently asked questions
What fertiliser does common ice plant need?
Balanced (even N-P-K) at planting for roots and frame, then switch to a high-potassium ("high-potash") tomato-style feed once the first flowers open — potassium is what sizes and ripens fruit, not nitrogen. Common Ice Plant feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.
How often should I feed common ice plant?
No feeding is needed in poor soils; if growing for leaf harvest, a single application of dilute balanced liquid fertiliser in spring will promote lusher foliage. No feeding is needed in poor soils; if growing for leaf harvest, a single application of dilute balanced liquid fertiliser in spring will promote lusher foliage. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).
What strength of feed for common ice plant?
Follow the crop-feed label rate for common ice plant — these are calibrated for hungry vegetables. Consistency through fruiting matters more than strength; erratic feeding causes problems like blossom-end rot.
What does over-feeding common ice plant look like?
Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen). Lush foliage hiding the crop; soft growth prone to pests and disease. Salt crust on the soil and scorched leaf edges in containers. Staying on a high-nitrogen feed once common ice plant starts flowering is the classic error — you get a huge leafy plant and a disappointing crop. Switch to high-potash the moment flowers appear.
Should I flush the soil of common ice plant?
In containers, fertiliser salts build up fast — water common ice plant thoroughly so excess drains from the base each time, and flush pots with plain water every few weeks to prevent a damaging salt build-up.
Keep reading
- Common Ice Plant care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water common ice plant — 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 florence fennel
- How to fertilise 'castelfranco' radicchio
- How to fertilise nasturtium 'empress of india'
- All 10153 fertilising guides in the Growli library