Walking around Carina and Victor Contini's flourishing Victorian walled kitchen garden at their home on the outskirts of Edinburgh on a dry, sunny day in April, it's difficult to recall its tricky beginnings in January 2012.

Over two years the hard graft involved the removal of a giant fallen tree, the filling of a deep pond, levelling off of the undulating land, the eradication of decades-old weeds and stubborn vegetation, the appointment of a head gardener, installation of a polytunnel and, finally, a major planting operation. It has all resulted in the most glorious, varied and productive supply of herbs, leaves, fruits and vegetables for the couple's two Edinburgh restaurants, the Scottish Cafe at the National Gallery of Scotland, and Ristorante Contini, formerly Centotre.

The house and garden have been christened Casa San Lorenzo, after the patron saint of cooking.

Such is the effect of growing locally and seasonally that The Scottish Cafe has already been awarded a three-star rating from the Sustainable Restaurants Association: chef Suzanne O'Connor uses every possible part of a plant and sends all unusable vegetation back to Casa San Lorenzo for composting. The restaurants source all other ingredients from 60 artisan suppliers around Scotland. Carina, who was the first female chef to be appointed to the Slow Food Alliance and was recently named a Scotland 2014 food ambassador, says: "Buying local, eating in season and maintaining our food heritage must surely be the focus of all our food choices.

"Scotland has finally regained its desire for good-quality food. People have learned that local, seasonal, sustainable food not only supports the environment but is also cheaper, tastier and healthier. Growing and cooking our own food, if we can, is the icing on the cake."

Carina is an Italian Scot whose grandparents, having left the mountains of Abruzzi, opened The Wemyss Cafe in Port Seton, when they arrived in Scotland in 1919. This developed into a thriving cafe, restaurant and catering business run by her parents for more than 70 years. Carina herself opened her first restaurant through Victor's family business Valvona & Crolla in Edinburgh in 1996, gaining plaudits such as Harpers & Queen Scottish Food Personality of the Year, and being named one of Scotland's Most Influential Food Personalities in The Herald.

The couple left the family business in 2003 and opened Centotre. Carina says: "My grandparents and parents fed thousands of people with simple, good quality, seasonal food. Fast forward almost 100 years, and my husband and I have now taken up the mantle. The journey to our kitchen garden has carried us full circle back to the land."

During the garden renovation, Carina kept a diary, and has now published a gorgeous cookbook with 120 Scottish recipes with an Italian twist, while also charting the garden's development under the original head gardener Erica Randall, who has now moved on to be replaced by Kerry Lyall, from the Royal Botanic Garden in Edinburgh. There are helpful growing tips too.

The garden is sure to be the envy of all aspiring gardeners: there are 49 apple trees in five heritage varieties, including White Melrose, James Grieve and Chivers Delight, as well as six varieties of espalier and cordon apples. A large asparagus bed, planted with advice from Pattullo of Glamis, is showing shoots but they will not be cropped until next year.

There's a light, airy polytunnel planted with support from supplier Robert Wilson of Scotherbs. Slabs have been laid as the foundation for a future greenhouse. There are Musselburgh leeks, kale, purple sprouting broccoli, rainbow chard and garlic. An area has been designated for soft fruits such as Scots raspberry varieties, morello cherries and strawberries; pink rhubarb is being forced under upturned black plastic bins. There are plans to plant heritage pear and plum trees along the ancient stone walls of the garden. The herb garden inside the polytunnel, fragrant with every leaf imaginable, was laid out by Kerry, who was a primary teacher in Leith, before a career switch and now runs her own one-acre kitchen garden at home in Aberlady. In the distance, through a gate, there's a "fairy garden" for wild foraging of wild garlic, elderflowers and so forth.

Gardens are, of course, living, breathing, things, and this one is literally buzzing with activity. Victor has two hives of native black honey bees which not only help pollinate the plants but also produce honey. Last season they produced enough honey to give 1.4kgs to Ristorante Contini and the same to the Scottish Cafe, and this year he's hoping for more. The jars will be labelled Casa San Lorenzo.

Kerry is advising Carina on how to rabbit-proof their precious soft leaves with fencing, and by clearing away debris under the walls; rabbits simply use this as a ladder to get where they want to get. There are free-range hens enjoying a dustbath in the sun. It's possible that rabbit and wood pigeon from the area might also be used in the restaurants in due course alongside chicken.

And in the large, airy, open-plan kitchen of the newly restored house, the Contini children - Orlando, 12, 10-year-old Carla and Arianna, eight - are clearly as at ease in the kitchen as their parents. It's all hands on deck to get lunch prepared, using recipes from their mother's new book. Arianna has made the lightest choux pastry buns, and is busy whipping a Chantilly cream to fill them, and coffee icing to decorate them. But before that, we sample a creamy carrot and parsnip soup, served in a tea cup with a dollop of apple puree drizzled with olive oil from Carina's brother's farm in Puglia, which has been in the family for 700 years. He revived the farm, which had been abandoned for 100 years, and now runs a successful co-operative with local olive growers.

Carina and Victor are passionate about the need for Scotland too to capture and nurture the skills involved in producing local food before they disappear.

A leek and thyme tart, covered with puff pastry, is sweet, warm and delicious, and we enjoy it with crisp, fresh salad leaves from the garden with pea-shoots, capers and beetroot. Then Carina serves up soft, warm, peppery spinach and crowdie drop scones, made with cheese from Highland Fine Cheeses in Tain. She feels crowdie has been overlooked in favour of other soft cheeses such as ricotta, and wants more people to use the ancient Scottish ingredient.

"Running a vegetable garden is hard work. Now that we're into our third season, we're being more strategic. We've learned what we can grow and what volumes we get from each crop. The next step is to get the correct crops in the correct volumes for the direct benefit of the restaurants.

"We're learning how to get the most out of each plant. For example, last year we used nasturtium flowers in salads, used their leaves for pesto, and this year we'll also pickle their seeds and use them as you would capers. And from our broad beans we got the early shoots for salads, the later shoots for stir-fries, the beans themselves, and the flowers for salads. We'd never have known about that if we hadn't grown them ourselves. To be able to get all those variations from one plant is amazing."

Carina Contini's Kitchen Garden Cookbook: A Year of Scots Italian Recipes is published on Thursday by Frances Lincoln, priced £25.