Fertilising guide

How to fertilise Common Iceplant (Mesembryanthemum crystallinum)— schedule & NPK

Also called Common Iceplant, Crystalline Iceplant, Ice Plant.

More about common iceplant

About Common Iceplant

Mesembryanthemum crystallinum · also called Common Iceplant, Crystalline Iceplant · edible

Common Iceplant is a sprawling annual succulent native to coastal South Africa and the Mediterranean, covered in glistening water vesicles that give it a frosty appearance. The succulent leaves have a crisp, mildly salty-sour flavour and are eaten raw in salads or lightly cooked like spinach. Grow in full sun, sandy soil, and minimal water once established.

Growth habit: Prostrate, mat-forming annual or short-lived perennial succulent

What fertiliser common iceplant actually wants — and why

Common Iceplant feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

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 iceplant: 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 iceplant, 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 iceplant:

Light feeding only — this plant is adapted to poor soils. A balanced fertiliser at half-strength once a month during the growing season is sufficient. Over-feeding reduces the characteristic salty flavour of the leaves. 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 iceplant 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 iceplant

Follow the crop-feed label rate for common iceplant — 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 iceplant first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the common iceplant watering schedule.

Signs you are over-feeding common iceplant

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

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 iceplant

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 iceplant 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 iceplant 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 iceplant

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 iceplant — frequently asked questions

What fertiliser does common iceplant 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 Iceplant 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 iceplant?

Light feeding only — this plant is adapted to poor soils. A balanced fertiliser at half-strength once a month during the growing season is sufficient. Over-feeding reduces the characteristic salty flavour of the leaves. Light feeding only — this plant is adapted to poor soils. A balanced fertiliser at half-strength once a month during the growing season is sufficient. Over-feeding reduces the characteristic salty flavour of the leaves. 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 iceplant?

What does over-feeding common iceplant 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 iceplant 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 iceplant?