Mesembryanthemum crystallinum

Sowing, spacing, and site selection

Mesembryanthemum crystallinum seeds prefer full sun and sharply drained, sandy or gritty soil, and will tolerate poor and even saline ground. Start seeds under cover in warmth and good light, then transplant carefully after last frost once seedlings are sturdy; in mild, frost-free climates, sow outdoors in the cool season or autumn. Direct sowing after last frost also works where soil is workable and drains freely. Growth is low and spreading, so space plants generously and avoid crowding to maintain airflow. Water lightly, allowing the medium to dry between waterings. Harden off before planting out, and avoid rich soils that encourage lush, weak growth.

• Full sun; sandy or gritty, free-draining soil; tolerates poor and saline conditions.
• Start under cover in warmth and bright light; transplant or direct sow after last frost; in mild, frost-free climates, sow in the cool season or autumn.
• Space generously for a low, spreading habit; thin to maintain airflow and reduce humidity.
• Container-suitable: thrives in wide, shallow pots with a gritty mix.
• Ornamental: glistening foliage adds sparkle and texture at the front of beds.
• Edible: young leaves may be harvested for culinary use; pick tender growth sparingly.

How do I grow Mesembryanthemum crystallinum from seed?

Sow Mesembryanthemum crystallinum seeds on the surface of a free-draining, sandy or gritty mix and press in lightly; they appreciate light for germination, so avoid burying deeply. Provide steady warmth and bright light, keeping the medium just moist—not wet—by misting or bottom-watering. Germination typically follows in a couple of weeks. Once seedlings have true leaves, pot on carefully and continue in full sun with sparing water. Harden off and transplant after the last frost. As a warm-season annual, it needs little feeding; allow the soil to dry between waterings and remove spent plants before cold sets in. It may self-seed.

When should I sow ice plant seeds in relation to the last frost?

Start seeds under cover in warmth and good light before outdoor conditions are suitable, then transplant after the last frost when the soil is reliably warm and nights are mild. Direct sowing can also be done once frost risk has passed and the soil is workable. In mild, frost-free climates, sowing in the cool season or autumn works well, avoiding peak heat and humidity. In all cases, protect young seedlings from cold snaps and prolonged wet, and acclimatise them gradually to outdoor sun and wind before planting out.

What soil and sun conditions are best for crystal ice plant?

Give crystal ice plant full sun and sharp drainage. A sandy, gritty, or rocky substrate is ideal; it tolerates poor and saline conditions, making it suitable for exposed, coastal-style sites where salt spray and lean soils are common. Avoid heavy, water-retentive mixes and low spots that collect water. If soil is dense, improve it with coarse grit or plant on a slope, berm, or raised area. Fertiliser is seldom necessary. Consistent drainage is more important than frequent watering; overwatering in rich soil is the most common cause of failure.

How far apart should I space crystal ice plant, and how tall does it get?

Crystal ice plant is low and spreading, typically forming a mat around 10–20 cm tall with a spread that can reach 30–60 cm or more in open ground. Space plants 25–45 cm apart, depending on how quickly you want coverage, leaving extra room where airflow is limited. Avoid crowding to reduce humidity around foliage, and keep neighbouring plants from shading it. In containers, allow similar surface area or choose a wide, shallow pot so the plant can sprawl without overlapping too densely.

Are the leaves of Mesembryanthemum crystallinum edible, and how do I harvest them?

Yes, the leaves and young stem tips are edible. Begin light harvesting once plants are well established and growing strongly, taking tender growth and avoiding removal of more than a third of the plant at a time. Pick in dry conditions, then rinse to remove any surface salt crystals and grit. Regular, modest picking encourages new shoots and helps keep plants compact. In very hot or dry spells, leaves can become more intensely saline; adjust harvesting to taste and growing conditions.

What’s the difference between Delosperma and Mesembryanthemum ice plants?

Both are “ice plants,” but they differ in habit and climate tolerance. Mesembryanthemum crystallinum is usually grown as a warm-season annual or short-lived succulent with sparkling, bladder-like leaf cells and a sprawling habit; it tolerates saline, nutrient-poor soils. Delosperma species are typically perennial groundcovers with narrow, fleshy leaves and abundant daisy-like blooms in vivid colours; they tend to be more cold-tolerant where drainage is excellent. Both prefer full sun and sharp drainage, but Delosperma suits long-term, dry rock-garden settings, while Mesembryanthemum is often used for seasonal coverage or edible greens.

Information synthesised from horticultural references and ongoing in-house trials. Recommendations reflect typical conditions and use climate cues such as “after last frost”, “when soil is workable”, or “in mild climates autumn sowing may be possible”. Outcomes vary with microclimate, soil, and seasonal variability. Product pages provide cultivar-specific instructions on sowing depth, spacing, and timing, which take precedence where provided.

Growing Ice Plant from Seed

Mesembryanthemum crystallinum thrives in bright sun and sandy, free-draining soil. For best germination, sow after the last frost or start indoors when conditions are warm and light is strong. Use a gritty, low-nutrient mix; press seeds onto the surface or cover very lightly, as they benefit from light to germinate. Keep moisture gentle and even; avoid waterlogging. Germination is typically quick in stable warmth. Once seedlings have formed sturdy growth, harden off gradually and transplant to a sunny, sheltered site with excellent drainage. Space plants to encourage airflow, and water sparingly once established; this succulent tolerates dry spells and prefers not to sit in wet soil. In mild climates, autumn sowing may be possible for earlier displays, provided the site remains frost-free. With ample sun and lean soil, plants form low, glistening mats and produce delicate blooms through the warmer months.