Jip Santen

Sea Aster

A salty Amsterdam local

Sea Aster (Aster tripolium) is a salt tolerant plant that can be found in the Netherlands at salt marshes near the coast, but also at the banks of het IJ in Amsterdam. The plant takes up the salt from the water, which gives the leaves their salty taste. This is why they are a beloved ingredient to cook with. We hope to grow some Sea Aster in Aquaponics as a part of our project 'Grain of Salt'.


Sea Aster - Zulte (Lamsoor) - Purple flowers of Sea Aster

General information

In Dutch the leaves of this plant are known as Lamsoor (lamb’s ear), and are consumed as a vegetable. This name can be a bit confusing, because it is used for two different plants. The ‘real’ Lamsoor is a plant called Sea Lavender, or Limonium vulgare. However, since the leaves of Sea Aster are sold as Lamsoor, way more people associate Lamsoor with Sea Aster than with Sea Lavender. Locally, they can be found along the banks of het Noordzeekanaal and het IJ. It can also be found in natural area 'het Houtrak', which is close to Amsterd. In the late summermonths these fields turn into a purple oasis.


Sea Aster - Lamsoor - Source: Galloway wild foods https://gallowaywildfoods.com/sea-aster-identification-edibility-distribution/

Leaves and flowers

From July until October, Sea Aster grows blue and lilac flowers that attract bees and butterflies. The leaves of Sea Aster can be eaten and are a bit similar to Spinach, but saltier in taste. The leaves can be harvested from April until July, before the flowers come up.

Salt tolerance mechanism

Sea aster has a special way to deal with a salty environment. The plant stores the whole surplus of salt in one leaf. This leaf is easy to recognize because it is a bit shriveled, has a different color (yellow-reddish) and is a bit thicker. At same point this plant looses this leaf and appoints a new one to be the salt reservoir. The picture below shows an example of such a salt reservoir leaf in the bottom left corner.


Sea Aster leaf acting as salt reservoir - The yellow-red leaf in the left bottom corner of this picture is acting as a salt reservoir. This leaf itself is very unhealthy, but it keeps the rest of the plant healthy since it lowers the salt concentration in the rest of the plant. 

Medicinal Properties

Sea Aster contains high amounts of Vitamin A, C and D. Vitamin A is crucial for helping the immune system work properly, and helping vision in dim light. Meanwhile, Vitamin C is useful for protecting cells and keeping them healthy, as well as maintaining healthy skin. Vitamin D helps to keep calcium and phosphate in the body, which is needed for maintaining healthy bones and muscles.

How to grow

To grow Sea Aster from seed, sow the seeds in March-April on some loose soil. Don’t cover the seeds with soil. They need light to germinate. Lightly pressing the seeds in the soil is enough. The lower temperatures at night promote germination. The seeds need sweet water to germinate, but once they are in the seedling stage they can tolerate brackish or salt water. With exposion to higher concentrations of salt, the growth of the plant will be reduced, but the taste of the leaves will be more interesting. Sea aster is a winter hardy, bi-annual plant that grows well in wet, nutrient-rich soil. It requires full sun. 

We are using the seed package of IVN nature education. They also did research about growing saline vegetables and herbs. We already started growing Sea Aster and Saltwort. It is a bit early, but since we are growing them in the greenhouse this should be possible. We left the Sea Aster inside for a week, and now put it in our cold greenhouse. It may take up to 6 weeks until the seeds germinate. Buckle up for some updates!


Sea Aster and Saltwort in their growing bags - We presowed seeds for Saltwort and Sea aster in the middle of februari. They are currently in our nursery and we are patiently waiting for them to germinate. We got the sowing kit from IVN nature education.  Jip Santen



'Zilt' by Anette van Ruitenburg, Ellen van Straten & Sabien Bosman