Agriculture accounts for roughly 70 percent of global freshwater use, and extreme weather events droughts, floods, and unpredictable rainfall are putting even greater stress on the systems that feed us. Strengthening water resilience requires not just incremental efficiency gains, but a rethinking of how and where we grow crops.
Controlled Environment Agriculture (CEA) offers a tangible way forward.
A Smarter Way to Grow
CEA refers to the cultivation of crops in environments where light, temperature, humidity, CO₂, and nutrient delivery are precisely managed typically in greenhouses or vertical farms. Unlike open-field farming, which is subject to the variability of weather and soil conditions, CEA allows growers to control every element of the plant’s growth cycle. The result is predictable yields, consistent quality, and the ability to produce year-round independent of climate or season.
When CEA is combined with hydroponic or soilless systems, the gains in resource efficiency are even greater. Instead of relying on soil, plants are grown in nutrient-rich water solutions supported by inert media such as stone wool.
The combination of soilless systems and mineral wool growing media like stonewool allows for an unprecedented level of precision in how water and nutrients are delivered to crops—and equally important, how they are reused.
Closing the Loop on Water Use
In a hydroponic CEA system, water circulates within a closed loop. Every drop that drains from the root zone is captured, treated, and returned to the system. Studies show that such systems can reduce total water use by 50 to 90 percent compared with conventional soil-based cultivation. For example, hydroponically grown lettuce has been shown to use just 20 litres of water per kilogram of produce, compared with about 250 litres per kilogram for field-grown lettuce.
These efficiency gains are not achieved at the expense of productivity. In cucumber production, greenhouse systems using soilless substrates have reached yields up to 270 tonnes per hectare, compared with just over 30 tonnes in the open field.
Controlled, soilless cultivation not only conserves water—it also maximizes the return from every cubic metre used.
Preventing Pollution and Protecting Nature
Traditional open-field systems are often leaky: nutrients and agrochemicals can escape into the soil and waterways, leading to eutrophication and the degradation of freshwater ecosystems. In contrast, CEA systems can be managed to achieve virtually zero emissions of water and nutrients. Recirculating solutions are disinfected, filtered, and carefully monitored, preventing contamination and enabling long-term reuse.
This shift from open to closed systems has implications far beyond water efficiency. By limiting runoff and pesticide use, CEA protects surrounding ecosystems, helps restore aquatic habitats, and frees up land for nature.
Controlled environment agriculture not only produces food more sustainably—it contributes directly to biodiversity and ecosystem restoration.
The Role of Stone Wool Growing Media
At the heart of many hydroponic systems lies the stone wool substrate, a material developed to provide an ideal balance of air and water for plant roots. Stone wool is chemically neutral, durable, and highly porous, allowing growers to fine-tune irrigation and nutrient management with exceptional accuracy. Its physical properties make it possible to maintain optimal moisture levels, avoid waterlogging, and precisely control drainage—all essential for closed-loop operation.
Grodan, a Danish company within the ROCKWOOL Group, has long advocated for the wider adoption of CEA and stone wool systems as part of a European strategy for water resilience. By combining advanced growing media with precision irrigation and data-driven management, Grodan demonstrates how technology can help agriculture contribute to climate adaptation and resource protection.
From Practice to Policy
While the technical benefits of CEA are well documented, scaling its adoption across Europe will depend on supportive policy and investment frameworks. Grodan welcomes the European Water Resilience Strategy and calls for explicit recognition of CEA as a key enabler of sustainable water management. Public–private partnerships, research funding, and clear standards for water reuse could accelerate the uptake of these solutions.
Operationally, success depends on sound water management practices: maintaining low-sodium supply water, disinfecting recirculated solutions, and using sensor-based fertigation systems that adjust irrigation timing based on real-time data. Where these measures are applied, closed-loop systems consistently deliver 20 percent water savings and 35 percent nitrogen reductions—without any yield penalty.
Towards a Water-Smart Agriculture
Europe now stands at a critical moment. By integrating CEA into its water-resilience and agricultural innovation agendas, the EU can turn sustainability from aspiration into practice—growing more with less, protecting the environment, and ensuring a resilient food system for future generations.
The evidence is clear: CEA and hydroponic systems using stone wool substrates can drastically improve how efficiently agriculture uses and safeguards water. They reduce consumption, prevent pollution, and enable circular reuse—all while supporting high-value crop production and economic competitiveness.
Sources
- Heuvelink, E. & Marcelis, L.F.M. Using Less Water When Growing Hydroponically. Grodan / ROCKWOOL.
- Heuvelink, E. & Marcelis, L.F.M. How Soilless Growing Has an Effect on Less Water Pollution. Grodan / ROCKWOOL.
- Grodan, European Water Resilience Strategy — Position Paper.
