Samphire - Sea Pickle: Planting, Growing and Harvesting

Botany and description

The genus Salicornia belongs to the Amaranthaceae family (previously classified in the Chenopodiaceae), which encompasses a wide variety of plants, ranging from herbs to bushes, known for their ability to adapt to diverse environments, including those with high salinity. This genus is characterised by its unique adaptations to saline environments, making it a fascinating subject of study for botanists and ecologists. The Salicornia genus comprises approximately 30 species, though this number may vary depending on classifications and recent scientific discoveries. These species are distributed across different regions of the world, primarily in coastal areas and salt marshes.

Species within the Salicornia genus share several distinctive traits:

• Fleshy stems: The plants feature succulent stems, often green in colour, which may turn reddish or purple with age, storing water to cope with the salinity of their habitat.
• Reduced leaves: The leaves are typically reduced to simple scales, minimising water loss through evapotranspiration.
• Absence of visible flowers: Salicornia flowers are small, often hidden within stem cavities, adapted for pollination in windy, saline environments.
• Salt adaptation: These plants possess physiological mechanisms enabling them to tolerate, even thrive, in salt-rich soils where few other plants can survive.

Salicornia species are primarily found in saline coastal habitats, such as salt marshes and intertidal zones (areas affected by tidal movements). They play a vital ecological role in these environments, contributing to soil stabilisation and providing habitat for numerous animal species. Their presence often indicates high salt concentrations in the environment, limiting competition with less salt-tolerant plants.

Their ability to survive and thrive in extreme conditions makes them of interest for ecological research, phytoremediation, and even agriculture in areas affected by soil salinisation. Glasswort and its relatives within the same genus continue to inspire innovations in saline ecosystem management and sustainable food production.

Did You Know? Glasswort possesses remarkable adaptations for surviving in its saline habitat, thanks to sophisticated physiological and cellular mechanisms. It manages excess salt through a process of sequestration and excretion, storing salt in vacuolar cells to keep it away from vital metabolic processes, then eliminating it through its leaves and stems when necessary. This strategy allows it to maintain optimal water balance and prevent salt toxicity, ensuring its growth and reproduction in conditions few other plants can tolerate. Moreover, its ability to perform photosynthesis even in the presence of high salt concentrations exemplifies its exceptional adaptation, making glasswort a model for studying salt tolerance in plant biology.

The Salicornia europaea, commonly known as European glasswort, is a fascinating annual plant adapted to saline environments such as salt marshes and coastal areas. In France and elsewhere in Europe, it is mainly distributed along coastlines, where it plays an essential ecological role in stabilising soils and providing habitat for various species. For example, salt marshes rich in glasswort serve as nesting grounds for several migratory and local bird species, such as avocets and black-winged stilts, which find both refuge and food there. Dense glasswort areas also act as nurseries for many fish and crustacean species, with fry and young crustaceans finding protection from predators and abundant food. Insects, including specific butterfly and bee species that feed on glasswort nectar, also benefit from these habitats, playing a crucial role in pollination processes within these environments.

European glasswort has a distinctive appearance with its fleshy, succulent green stems, which may turn reddish as autumn approaches. The plant can reach up to 30 cm in height, often forming dense mats or clumps. Its unique structure is perfectly adapted to water retention in saline environments.

Salt marshes of Guérande (44): glasswort thrives here

These fleshy, jointed and segmented stems give the plant its characteristic “green coral” appearance. The leaves are reduced to simple scales, fused around the stem, minimising evaporation surface area and allowing the plant to conserve water in its saline environment.

European glasswort flowers from July to September. The flowers are tiny, almost invisible to the naked eye, inserted into the stem joints. Despite their small size, they play a crucial role in the plant’s reproduction.

The seeds of Salicornia europaea are small and produced in large quantities at the end of the growing season. They are dispersed by water or animals, enabling the plant to colonise new habitats.

Glasswort roots are relatively shallow but effective at absorbing water and nutrients from saline soils. They also anchor the plant in often shifting, unstable substrates.

Glasswort scales and stems: green coral!

An edible plant? Absolutely!

Glasswort, with its richness in minerals such as iodine, magnesium and potassium, as well as vitamins A, C and D, stands out for its beneficial nutritional profile. In cooking, it can be used fresh in salads to add a crunchy, salty touch, or steamed as an alternative to asparagus, garnished with a knob of butter or a squeeze of lemon. Its unique flavour, both marine and salty, works wonders in fish and seafood dishes, adding an oceanic dimension. Chefs also appreciate it for its ability to enhance flavours in vegetarian dishes, offering a healthy and tasty alternative to traditional herbs.

Glasswort also traditionally accompanies buckwheat galettes (photo Bloc notes culinaire)

Good to know: it’s a different botanical genus, but there is a Japanese glasswort that can also be grown in our vegetable gardens. The Japanese glasswort, (Salsola komarovii), is a distant annual cousin of our European glasswort. It’s also known as Land seaweed, Japanese sea bean or Okahijiki in Japanese. Its natural habitat is sun-drenched salt marshes along the northern coasts of China, Korea and Japan. The plant is characterised by its fleshy stems, harvested young for consumption, offering a crunchy texture and a flavour that’s both salty and iodised, reminiscent of the ocean. Used in traditional Asian cuisine, Japanese glasswort enhances sushi, elevates salads, serves as a side dish similar to green beans, or can be enjoyed pickled in vinegar.

Our finest varieties

[product sku=”184151″ blog_description=”European Glasswort or Salicornia europaea is an annual plant, also known as Sea Pickle, which sums up its main use quite well. It’s a wild plant that can also be grown in the vegetable garden.” template=”listing1″ /]

[product sku=”16989″ blog_description=”Japanese Glasswort, in Latin Salsola komarovii, is an annual plant similar to our European glasswort, sometimes called Land Seaweed, Japanese Sea Bean or Okahijiki in Japanese. This glasswort produces succulent stems that are eaten when young.” template=”listing1″ /]

Planting samphire

Where to plant?

Choose a sunny spot, as glasswort thrives under direct sunlight.

Glasswort flourishes in saline soils, so to cultivate this plant in a non-coastal garden, it’s necessary to simulate these conditions. Use a sandy substrate to ensure good drainage and add sea salt to the irrigation water (5g per litre) to increase soil salinity. Of course, to avoid raising soil salinity in your garden, which would harm other plants, consider growing glasswort in containers or pots instead.

However, for gardens near the coast, glasswort can be planted directly in the ground in areas that replicate its natural growth conditions, such as gravel gardens or rockeries.

Replicate glasswort’s natural growing conditions

When to plant?

Wait until the risk of frost has passed and the soil temperature has risen sufficiently. Glasswort germinates best when the soil is at least 15°C, which typically corresponds to April or May in the northern hemisphere, depending on the local climate.

How to plant?

Transplanting European glasswort is quite delicate, but young plants in buckets or as plug plants are available commercially. Plug plants are likely the best compromise between sowing and planting an already well-rooted plant. However, here’s how to sow your glasswort:

• In spring and in a sandy substrate, which mimics glasswort’s natural coastal environment, sow the seeds on the soil surface, as they need light to germinate. You can cover them with a very thin layer of soil or sand, but ensure they aren’t buried too deeply.
• Sow the seeds in rows spaced 20 to 30 cm apart, scattering them lightly to allow proper plant development.
• After sowing, water gently with slightly salted water to avoid dislodging the seeds.
• Keep the soil moist but not waterlogged during germination.
• Glasswort seeds should germinate within 7 to 14 days, depending on temperature and moisture conditions.
• Harvesting can begin when the plants have reached a suitable size, usually a few weeks after germination. Harvest young shoots for optimal crunchiness and flavour.

For planting bucket or plug plants:

• Plant in spring, after any risk of frost, when the soil begins to warm.
• Make holes spaced 20 to 30 cm apart to allow proper plant development. Row spacing should be about 30 cm for easy access and air circulation.
• Carefully remove the plants from their buckets or handle plug plants very gently, taking care not to damage the roots. Place each plant in a hole and adjust planting depth so the collar is level with the soil. Backfill the holes and lightly firm the soil around the plants to remove air pockets.
• Water immediately after planting with slightly salted water to help the plants establish and begin adapting to their new environment.

Maintenance of Samphire

Caring for European Glasswort (Salicornia europaea) in the vegetable garden requires simulating its natural habitat to promote growth. This involves watering with slightly salted water.

• Salinity: Glasswort requires regular watering with slightly salted water to mimic its natural environment. You can add around 5 grams of sea salt per litre of water. However, always start with a fairly weak concentration and observe the plants’ response, adjusting salinity as needed.
• Frequency: Water enough to keep the soil moist but not waterlogged, especially during dry spells. The watering frequency will depend on climate conditions and the soil’s ability to retain moisture.

Harvest and preservation of samphire

Propagation of Glasswort

European glasswort is primarily propagated by sowing, as this annual plant does not spread easily through propagation by cuttings or division. Here are the steps to multiply glasswort by sowing:

Harvesting seeds

Wait until the end of the growth season when the plants have produced seeds. The stems will turn reddish and the seeds can be harvested once they are dry. Gently shake the stems over a container to collect the seeds or rub the spikes lightly between your hands.

Seed preparation

Glasswort seeds can be sown directly without any prior treatment. However, for colder regions or to extend the growth season, you can start sowing indoors.

Indoor sowing

• Early sowing: Start sowing indoors about 4 to 6 weeks before the last expected frost.
• Containers and soil: Use small pots or sowing trays filled with a sandy compost mix. Ensure the container has good drainage.
• Watering: Water the seeds with slightly salty water after sowing, keeping the substrate moist but not waterlogged.

Outdoor transplanting

• Hardening: Before transplanting the young plants outdoors, gradually acclimatise them to outdoor conditions over a week.
• Planting: Transplant them outdoors in well-drained soil and full sun, spacing them approximately 10 to 15 cm apart. Continue watering with slightly salty water.

Direct outdoor sowing

• Timing: Sow directly outdoors in spring, after all risk of frost, when the soil has warmed sufficiently.
• Light sowing: Scatter the seeds on the soil surface or under a very thin layer of soil. Water with slightly salty water.
• Spacing: Sow the seeds about 10 to 15 cm apart to allow proper development.

Diseases and parasitic pests

Diseases

Although very resistant to diseases, European glasswort can, if cultivated in the vegetable garden, in open ground or in pots, encounter some minor issues.

Caused by excessive watering or poor drainage, root rot is a common problem for many plants, including glasswort. Therefore, ensure adequate watering and especially well-drained soil or substrate to avoid any problems.

Although less common due to its preferred habitat in full sun and its need for well-drained soil, powdery mildew can sometimes affect glasswort if conditions are too humid or if air circulation is insufficient. Make sure your glasswort is not smothered by other plants or planted in too confined a space.

→Learn more with our article Powdery Mildew: How to Prevent and Treat This Disease?

Parasites

Aphids can attack glasswort, particularly on young shoots. They suck the sap of plants, which can weaken the glasswort and make it more susceptible to diseases.

→ To learn all about aphids, read the advice sheet Aphids: Control, Treatment and Prevention.