is "lixiviated" from the ashes (extracted with water), and the resulting solution is boiled dry to obtain the finished soda ash product. A very similar process is used to obtain potash (mainly potassium carbonate) from the ashes of hardwood trees. Because halophytes must also have potassium ions in their tissues, even the best soda ash derived from them also contains some potash (potassium carbonate), as was known by the 19th century. Plants were a very important source of soda ash until the early 19th century. In the 18th century, Spain had an enormous industry producing barilla (one type of plant-derived soda ash) from saltwort plants. Similarly, Scotland had a large 18th-century industry producing soda ash from kelp; this industry was so lucrative that it led to overpopulation in the Western Isles of Scotland, and one estimate is that 100,000 people were occupied with "kelping" during the summer months. The commercialization of the Leblanc process for synthesizing sodium carbonate (from salt, limestone, and sulfuric acid) brought an end to the era of farming for soda ash in the first half of the 19th century. Cultivation and culinary uses The Italian name agretti is commonly used in English to refer to the edible leaves of S. soda; barba di frate (or friar's beard) is the most common of the Italian names. This plant is not a summer green and should be started early indoors or in autumn. The seed is notorious for poor germination at about 30 to 40% standard, much like rosemary. Though the plant is often grown in saltwater-irrigated land in the Mediterranean Basin, it will grow without salt water. S. soda is harvested in bunches when small, or cropped regularly to encourage new growth when mature. It is most commonly boiled and eaten as a leafy vegetable; the recommendation is to cook it in boiling water until the leaves soften, and to serve while some bite (crunch) remains (much like samphire). It can also be eaten raw; it is said to taste "grassy and slightly salty with a pleasant, crunchy texture". Salsola soda is sometimes confused with a plant known in Japan as okahijiki (land seaweed), which is actually the species S. komarovii. The harvested leaves of the two species have a similar appearance. Phytoremediation Salsola soda has also been studied as a bioremediation "biodesalinating companion plant" for crops such as tomatoes and peppers when they are grown in