Growing produce is easier in some places than others, however. Just ask the team at Singapore’s Edible Garden City that supplies fresh produce to about 70 establishments a week, including Fiamma by Chef Mauro Colagreco whose restaurant Mirazur on the French Riviera was crowned World’s Best Restaurant in 2019, as well as Restaurant Labyrinth and Open Farm Community.

It also helps restaurants build and maintain edible gardens within their premises, and has partnerships with hospitality groups and hotels, including 1-Group, Marina Bay Sands, and ParkRoyal Collection Marina Bay.

One of the major challenges of growing produce in Singapore is the island’s soil. Classified as Utlisols, it is highly acidic, primarily consists of red clay, and has low fertility. For example, it is particularly difficult for non-native crops such as tomatoes to grow in clay-dominated soils because they are susceptible to fungal wilts and other soil-borne diseases.

“A gardener or farmer usually has to do substantial work to the ground, amending and tilling the soil to introduce the nutrition and aeration plants require to flourish. It takes a few years to build up the soil for cultivation,” says Bjorn Low, Executive Director and Co-founder of Edible Garden City.

Ground-level gardens may have buried construction rubble, while rooftop gardens may have clay subsoil derived from the construction industry, which is usually poor in nutrients and drainage. Access to agricultural waste materials, the core building blocks of making good compost, is limited.

Meanwhile, importing good cultivable soil, such as from Malaysia, may negatively affect the landscape and the environment in the country of origin, not to mention the carbon footprint of transporting such a heavy material.

The significant effort required to develop healthy, fertile soil locally may be substantial, especially if “done naturally through composting and letting soil replenish itself,” rather than using chemicals that “can have devastating effects on our environment,” says Low.

Related: Fiamma: Capella’s new Italian spot by Michelin-starred Mauro Colagreco

But the benefits of healthy soil are immense.

“Soil health is foundational to all plant life. It promotes good plant growth. Thus, it also affects everything else in the ecosystem, including us and our quality of life,” he says.

Quality of life includes health, as well as the enjoyment of eating and drinking. As chef Paul Ivić of Vienna’s vegetarian hotspot TIAN, which has both red and green Michelin stars, says: “The soil is everything. If the soil is bad, there’s little taste and no nutrition.”

Ivić has spent the last decade setting up a network of local farmers, foragers, fermenters and winemakers who share his philosophy of respecting the environment and all the processes and people involved in getting food onto a plate or a drink in a glass.

Christian Tschida, a leading light in the global natural wine movement, has vineyards near Vienna in Illmitz, and supplies wines to TIAN. The concept of terroir has long been associated with expressing a sense of place through wine, and Tschida’s wines are particularly inspired by the soils of this eastern region of Austria, which contains schist, flint, quartz, and iron.

“What I want to do is make wine that reflects the origins, the soils of my vineyards,” he says. “Fifteen years ago I wanted to be the greatest and most complex winemaker. Now I want to be the simplest.”

Using cow manure from local farms left to compost for a year, Tschida expanded his composting system in 2015. In addition to repairing degraded vineyard soil, organic compost improved the soil’s ability to withstand climate change.

“I should’ve started 10 years earlier,” he says. “It takes five to 10 years to repair soil and prepare it for dry periods — something we’re seeing more of every year now.”

Related: Farming in the concrete jungle

To become resilient, the soil must be healthy. Additionally, it determines where plants thrive.

British chef Luke Farrell grows niche Thai herbs, spices, fruits and vegetables in an organic greenhouse in rural Dorset, England, for Asian restaurants in London, including his Southern Thai canteen Plaza Khao Gaeng and Speedboat Bar, modelled after the neon-lit restaurants of Chinatown in Bangkok.

The long-time Bangkok-based chef went to a horticulture specialist to recreate the soils of Thailand for his greenhouse at Ryewater Nurseries, mixing in coir, clay and leaf mulch to create a “rich Thai jungle soil mix”. Furthermore, he created conditions for below-ground fungal networks, bacteria and soil microbes to thrive. To ensure that the seeds are the right variety, he sources them from Thailand.

Growing the greens locally, Farrell says, is the only way to offer an authentic taste of Thailand in the UK.

“Southern Thai cuisine is the most difficult to recreate outside the country, as it’s so dependent on curry pastes that aren’t readily available elsewhere, and on fresh ingredients that cannot survive the journey of being transported across the world, or at the least lose their punch in the process,” says Farrell.

“So I set up supply lines for the curry pastes, and I grow the correct chillies, turmeric, and herbs myself. I use the herbs seasonally; they are in a greenhouse, but there are still seasons like in Thailand.”

It has not been an easy process. Thai long pepper was a particular challenge; the flowering vine is difficult to grow and is pollinated by bats — a tricky requirement in a greenhouse. He tried pollinating by hand using a tuning fork, but failed. Cinnamon leaf, or Indian bay leaf, took much trial and error but is now a success.

To recreate subsistence farming on the Mekong river’s richly silted, sandy soil, Farrell is erecting another greenhouse 35m long and 9m tall. His plantings will include bananas for their stems, leaves and the green fruit for salads, interspersed with everything from holy basil and chillies to passion vines and snake gourds. Lotus roots, water lily stems, morning glory, and water chestnuts will be planted in a water tank that runs the length of the space. Mekong snail-eating turtles and catfish will also have a home. The greenhouse will be in bloom next year, he predicts.

Whether in an urban rooftop garden or a rural greenhouse, growing plants indigenous or imported, soil is the substrate that underpins it all.

In addition to chefs and winemakers becoming increasingly aware of soil health issues, diners also have a role to play: “All of us can do our part by knowing how our food is grown and by supporting farmers who grow food naturally without harmful chemicals and pesticides,” says Low of Edible Garden City.

Related: From garden to table: More restaurants and bars are growing their produce in urban farms