Mara Seaweed, the ­Scottish food start-up that has won prestigious shelf-space in Harrods food hall, Valvona & Crolla, and Harvey Nichols, moves into new premises in Granton this week to allow a surge in production.

It has launched an 18-month pilot project into bulk seaweed farming as it targets £7 million in branded global sales by 2019.

Founded by Fiona Houston and Xa Milne, Mara has won praise from chefs like Paul Hollywood and Michael Smith at Skye's Three Chimneys for reviving the tradition of harvesting and processing seaweed for the table. Last week it was shortlisted for a UK-wide Footprint award, the only food company in the running for the sustainable business prize.

Employing seven people, Mara (sea in Gaelic) mills and packages premium quality seaweed, both as an ingredient and a healthy salt alternative. The products include shony, kombu and dulse. As well a prospective "farm" in Loch Fyne, the firm has a licence from the Crown Estate to harvest seaweed from Fife, and is seeking further permissions.

A Scottish Enterprise high-growth company, Mara was launched with a £450,000 investment, and has since spent £140,000 on new milling and drying plant. The firm is seeking a further £150,000 from private investors.

The pilot project "Seaweed for Sustainable Economic Development" is a collaboration between Mara, the Oban-based Scottish Association for Marine Science (SAMS) and Otterferry Seafish.

This year Mara anticipates sales of £245,000 of its "ancient food for modern thinkers", which it expects to grow by a factor of 10 after two years of global sales. Ms Houston said: "Seaweed is a massive opportunity for Scotland, and we're just at ground level. Our aim is to go from wild harvest to a mixture of farmed and wild, with seaweeds specifically selected for tastes and flavours.

"All of the 3000 or so species of seaweed are edible, but only some taste good. This is a product to enjoy. We don't want to sell a boring health product taken in pills."

A "superfood" that was a staple for coastal Scots from prehistoric times until the 20th century, seaweed is the most highly mineralised vegetable on earth.