This week I bring tidings of a bold new venture being launched on Thursday.

Herbalist Hamish Martin and his wife Liberty are transforming a 7.5-acre organic plot into the Secret Herb Garden, which they say will become much more than a herb nursery. Their greenhouse and cafe open next week and, in time, will be followed by orchards, a rose garden, herb beds and more.

You couldn't hope for a more attractive sales area than the large, renovated greenhouse. Martin hopes people will be inspired by the beauty of the place, whose wide paths will be lined by fruit trees - peaches, apricots, figs, grapevines, old varieties of pears and the popular new apple-pear cross, Nashi or Asian pears. He wants his tranquil green space to be "a jungle of herbs where you can lose yourself".

The garden in Damhead, near Edinburgh, has a staggering selection of herbs for sale. There is the full range of hardy sages which can be grown outdoors in Scotland, as well as the slightly more tender tangerine, pineapple and blackcurrant varieties. Martin tells me he has 12 rosemary varieties and more than 60 mints, including the exotic Balm of Gilead or gingko.

As a general rule, though, Martin wants to promote plants more suited to the Scottish climate. He also stocks the likes of parsley and chervil, herbs which are easier bought as plants than grown from seed.

His definition of herbs is much broader than that of many people, and takes in angelica, sweet cicely (Myrrhis odorata) and tansy (Tanacetum vulgare), and he is also keen for gardeners to re-evaluate what they view as weeds. In one greenhouse bed, he uses chickweed as a type of mulch round his garlic and then sells the chickweed to restaurants for use in salads. He also supplies ground elder, cleavers and nettles. As we pass a bed of nettles he tells me: "See these nettles? They're all my friends."

It's easy to forget that petals can have a more delicate flavour than other parts of many plants, so it is refreshing to see roses grown for their culinary value as well as their beauty, among them the apothecary's rose (Gallica officinalis), damask roses and Zephirine Drouhin. Other edible flowers include cowslips, primroses, nasturtiums, marigolds and the mallows - marsh (Althaea officinalis), musk (Malva moschata) and common (Malva sylvestris).

Old-fashioned herbs such as elecampane, feverfew, costmary and the artemisias are also grown. Martin hopes people will discover that these quirky, beautiful plants also have their uses. It's encouraging to see rhubarb interplanted with sweet cicely, both of which coincidentally featured in the pork stew I ate the evening before my visit.

The Secret Herb Garden has much going for it, then. The cafe and delicatessen feature herbal and locally sourced goodies, including home-brewed beers, and visitors will be able to fill a picnic basket and explore the garden. As they climb a hill, they'll pass raised beds, each dedicated to a particular herb species.

It's delightful to see that the orchard has been planted with traditional Scottish apples, including Beauty of Moray and Clydeside. There are pears, plums, gages, medlars and even mulberries. Half a dozen beehives provide a bonus. Watching the hard-working bees can be mesmeric and visitors may be inspired to enrol on a beekeeping course run by the garden's expert Brian Pool. With views of Arthur's Seat and the Pentlands, the backdrop is impressive.

The Martins aim to widen the appeal of the garden by displaying old garden tools and furniture as well as running courses on cookery, making cosmetics, candlemaking and medical herbalism. It'll be hard to keep this place a secret.

The Secret Herb Garden, 32A Old Pentland Road, Edinburgh. Visit secretherbgarden.co.uk.