In our imagination, agriculture is often associated with tractors, large fields, and grazing cows. But economic, ecological, and societal realities are now forcing us to rethink this model of agriculture if we want to regain control of our food autonomy in the context of climate change.

Among the existing avenues for designing a form of agriculture capable of meeting these challenges, soil-less production has certain advantages, but also major disadvantages. Complementary to other approaches, it will by no means solve the issues on its own.

Climate change, urbanization, and loss of agricultural land

Climate change, through the short but intense and frequent extreme weather events it causes, is already having a profound impact on agricultural production in certain regions of the world. It is accelerating migration to cities, a process that since 1950 has already caused the urban population to jump from 30% to 60% of the world's population. The latter continues to grow: from 8.2 billion people today, it is expected to reach 9.66 billion in 2050, which also poses a major challenge for food security.

At the same time, the main providers of food, namely the soil, are also under threat.

On the one hand, through artificialization, which is directly linked to urbanization and manifests itself in France through the annual disappearance of 24,000 hectares of natural or agricultural land to make way for urbanization and industrialization.

And on the other hand, through productivist agriculture, which contributes to weakening and taking control of agricultural land and natural spaces, particularly forests: worldwide, between 43 and 45 million hectares of land have been subject to land grabbing by agri-food giants, land speculators, mining companies, elites, and government officials in order to deploy monocultures (palm oil in Indonesia, soybeans in the Amazon, industrial vegetable crops in Western Europe, etc.) that damage the soil, sometimes contribute to deforestation, and only reinforce the food dependency of certain territories.

All these factors threaten food security and are already causing tensions, including in France, as we saw in Martinique in October 2024, when violence broke out in protest against food prices that were 40% higher than in mainland France.

Soilless production

Faced with these complex situations, our agricultural systems need to evolve. One agrosystem that aims to address the lack of agricultural land, climate uncertainty, and the need for relocation is soilless agricultural production. It is characterized by the ability to control all or part of the growing environment (light, temperature, humidity, water, nutrients, CO₂, innovative substrates/supports, etc.).

Above all, it helps mitigate the effects of climate change such as drought, flooding, and late frosts, and requires little water. Some soilless farms are set up in renovated buildings, basements, or on rooftops, which does not take up new agricultural land. This type of facility, located close to city centers, enables local, low-input production, which limits export costs and avoids potential soil contamination.

It can be integrated into urban, peri-urban, or rural agriculture and contribute to the redevelopment of abandoned and/or polluted industrial wastelands, or be incorporated into farms as a means of diversification. This requires perfect control of the physical, chemical, and biological parameters of plant growth: first, control of substrates, growing media, and root anchoring; then, control of fertilization to meet the nutritional needs of each plant.

Hydroponics, aeroponics, and aquaponics

These systems take three main forms.

The best known to the general public is hydroponics: most tomatoes, cucumbers, zucchini, lettuce, and strawberries grown above ground are cultivated using this technique. This method provides all the essential nutrients to the plant in the form of a liquid flow. There are several types: deep water culture, where the roots are immersed in large quantities of water and nutrients; tidal table, where nutrients are supplied twice a day by a system that raises and lowers mineral-rich water in the growing tray; and NFT (Nutrient Film Technique), in which a continuous flow of nutrient solution circulates without completely submerging the roots, thanks to a slightly sloped, watertight, dark channel.

Aeroponics, on the other hand, is a method similar to hydroponics that involves spraying pesticide-free nutrients directly onto the roots in the form of a mist, tailored to the requirements of the species being grown. The roots are isolated from the canopy and placed in special containers that keep them in darkness. This optimizes root oxygenation, reduces the risk of disease, and promotes plant development.

Finally, aquaponics, which combines aquaculture and hydroponics, uses the waste from fish raised in tanks (in a dedicated room) to feed the plants. In return, the plants take up the nutrients and clean the water with the help of bacteria. The bacteria make the nutrients available and assimilable by the plants. Perfect harmony and teamwork!

Highly criticized techniques

However, these so-called above-ground techniques are the target of much criticism: they are said to produce tasteless fruits and vegetables that never see the ground or the sun, or herbs and microgreens that “don't feed a man.” Social and cultural acceptance of these techniques varies greatly from country to country. While soilless cultivation enjoys a good image in the United States and Asia, Europeans are more skeptical about eating fruit and vegetables that have not grown in “real” soil.

From an economic standpoint, the investment cost is high, ranging from tens to hundreds of thousands of euros. And the other major cost is energy – despite progress, a salad grown using conventional agriculture tends to have less impact on the environment than a salad produced year-round using soil-free methods.

In this context, many high-tech companies that had rushed into this model have already closed down due to lack of profitability: the aromatic herb start-up Jungle, the strawberry and salad producer Agricool, and Infarm, which offered hydroponically grown vegetables, have not survived.

One solution among many

Today, the aim of these small-scale systems, which offer limited varieties, is not to feed an entire population, but simply to contribute to the food self-sufficiency of cities. These new farms also have the educational advantage of reconnecting citizens with agricultural production and providing an interesting way to learn about the life cycle of a plant.

In addition, these farms could diversify their activities in order to remain viable by turning to the production of animal feed, alternative plants to animal proteins, or even plants for the pharmaceutical industry (high value-added molecules).

Far from sounding the death knell for traditional agriculture, soilless production can instead add to its efforts in the quest for food self-sufficiency.

We would like to thank Alice Legrand, Lisa Ménard, and Clémence Suard, students who contributed to the writing of this article and brought their perspectives as young agronomists to our discussion.