We heard of indoor farming, vertical farming, and even underground vertical farming. In theory, indoor farms can be placed anywhere in the world as crops can be grown in a protected and controlled environment independently of any “outside conditions”. Indoor farms can be build in hazardous environments, from the Arctic to the International Space Station or on Mars. However, have you ever thought about indoor farms under water? The OCEAN REEF Group is pushing the boundaries of agriculture by cultivating plants under water. This is by far the most amazing concept of future agriculture that I have heard of so far, and I will share with you why.
Nemo's Garden is an underwater farm near Noli, Italy, comprising of six clear plastic pods or spheres anchored to the sea floor. Each pod holds 2,000 liters of air and is positioned at depths of 5-10 meters. Divers operate from step grids, with half their bodies above water. Inside the pods, water condenses on the walls, providing natural hydration, while stable sea temperatures create ideal growing conditions day and night. This innovative project demonstrates the potential of underwater farming for sustainable agriculture. While very intriguing, further research, both on crop cultivation and technical implementation, is necessary, before underwater farming becomes a viable cultivation technique in the future. Let’s dive into the details:
The Birth of Nemo’s Garden
The idea for Nemo's Garden was conceived by a group of Italian entrepreneurs and marine enthusiasts, led by Sergio Gamberini. Sergio Gamberini, the mind behind the project, found the perfect bridge between his passion for gardening and his expertise in underwater equipment development. The idea of an underwater greenhouse emerged in 2012 as a novel approach to address some of the challenges associated with traditional agriculture, such as land scarcity, climate change, and the need for sustainable food production.
Why growing underwater? The team was inspired by the idea of utilizing the vast and relatively unexplored underwater space for agricultural purposes. They envisioned creating biospheres beneath the surface of the sea where plants could be grown in a controlled and protected environment. This environment would exploit the natural benefits of the ocean, such as stable temperatures, access to water, and protection from extreme weather events.
As an interesting side note: The name, “Nemo’s Garden” was inspired by Captain Nemo from the novel "Twenty thousand miles under the sea" (by Jules Verne) who lived in an advanced underwater habitat.
Over the years, Nemo's Garden has evolved from a concept to an experimental project, with the team conducting various trials and experiments to refine the techniques and technologies needed for successful underwater farming. They have grown over 50 different plant species, including herbs like basil, and continue to explore the potential of underwater agriculture for the future.
How does it work?
Nemo's Garden relies on key factors including temperature, illuminance, and indoor humidity to facilitate plant growth inside the biospheres.
The transparent domes, anchored to the seabed, replicate the water cycle on a micro scale. Direct sunlight passes through seawater and the dome's polymeric film. Water evaporation-condensation in the biosphere creates fresh water for plant growth, cretinga self-sustainable system. The purified condensation water can be used to irrigate plants, while the surrounding sea acts as a thermal energy reservoir. Nemo's Garden primarily employs hydroponic-based greenhouse gardening. This method involves growing plants without soil in a controlled environment, using a nutrient-rich solution to nourish their roots.
Their definitely unique approach eliminates the need for traditional greenhouse resources like power, temperature regulation, and LED lighting. Instead, it features a 10-meter spiral tube with 60 seedbeds containing stone wool. Water and fertilizer are stored in a tank at the lowest point of the spiral. A water pump circulates the mixture, providing nourishment and oxygen to the plants. Solar panels power a fan, which helps maintain optimal humidity levels on the plants' leaves. The environmental conditions inside the spheres are monitored 24/7 and send to a control tower on land. The stability of temperature, relative humidity, and illuminance is crucial for successful plant growth. In the spheres, thermal fluctuations in seawater and air are relatively constant, contributing to the water condensation process.
And how are the plants harvested? While the thought seems very complicated, the solution is simple: divers transport the harvested plants in small plastic bags to the surface.
Are plants of the same quality when grown underwater compared to on land?
Several studies have been conducted on the quality of crops grown in Nemo’s Garden. In 2020, it was discovered that basil grown in Nemo's Garden biospheres exhibited remarkable improvements in yield, flavor, and nutritional content. Plants cultivated within the biospheres displayed higher concentrations of total chlorophyll, total carotenoids, and total polyphenols compared to plants grown on land in a greenhouse. Impressively, antioxidant activity and polyphenol content were elevated by 31.52% and 13.3%, respectively, in biosphere-grown samples.
Also Stevia plants (also known as sugarleaf, Stevia rebaudiana) showed no decrease in quality if grown underwater. Both underwater and terrestrial samples showed similar chemical profiles, featuring phenolic compounds and steviol glycosides. While the underwater environment preserved the plant's micromorphology, it elicited slight qualitative changes in response to the distinctive growth conditions, underscoring the potential of underwater farming for sustainable agriculture.
Underwater farming vs. traditional greenhouse cultivation
There are a few environmental advantages of underwater biospheres over traditional land-based greenhouses. The ocean's natural temperature regulation reduces the need for energy-intensive heating and cooling. The desalination process eliminates the need for freshwater sources, and the absence of pests ensures a contamination-free environment.
Unfortunately, there are a few drawbacks of underwater farming. While there are no plant-pests living in the surrounding seawater and the risk of an infection is drastically reduced, there is still a possibility to bring in pests from the outside (especially via plant material). Additionally, light can be very dim under water. While enough light might penetrate through the domes during summer, not enough light reach the plants in winter. Low light intensities reduce the possibility of growing many crops, especially fruit and vegetable bearing plants. Furthermore, installation and maintenance costs are very high in relation to the amount of plants that can be grown in one sphere. While Nemo's Garden is exploiting the stable temperature conditions for underwater farming, it also faces a unique set of vulnerabilities. Major natural disasters like storms or tsunamis pose potential risks, emphasizing the need for robust contingency plans and protective measures.
Despite this, we have to keep in mind that Nemo's Garden is a very novel and innovative project exploring underwater crop cultivation. Venturing into the underwater realm presents unique challenges. Overcoming the limitations of electricity conductivity underwater, ensuring the durability of electronics, and adapting to the buoyant environment have all required innovative solutions. The absence of a guidebook for underwater cultivation has pushed the Nemo’s Garden team to explore uncharted waters.
A Glimpse into tomorrow’s agriculture
Currently, Nemo's Garden has 9 operational biospheres, housing over 600 thriving crops, the project demonstrates the potential of sustainable underwater cultivation. A new, highly efficient hydroponic system has allowed for diverse plant species cultivation, showing promising results. At the moment, Nemo’s Garden is in the process of building a 9-meter-long, 2-meter-wide, and 1.2-meter-high artificial reef to analyze water current speed and explore the potential for energy production to support the on-land-lab's utilities. Ongoing experimentation with desalination systems brings Nemo's Garden closer to achieving self-sustainability. Intriguingly, the surrounding sea life has also flourished, showcasing the project's positive impact on marine biodiversity. This progress marks a significant step towards a more sustainable and environmentally conscious future in agriculture.
I’m very curious to see what the future of Nemo’s Garden will hold.
Selected references
Devi, N. S., Hatibarua, P., & Devi, N. B. Nemo’s Garden-the world’s first-and only-subterranean greenhouse (A review article).
Ascrizzi, R., De Leo, M., Pistelli, L., Giuliani, C., Pieracci, Y., Ruffoni, B., ... & Pistelli, L. (2022). Resilience of Stevia rebaudiana (Bertoni) Bertoni in the Underwater Biospheres of Nemo’s Garden®: Adaptation to New Cultivation Systems. Molecules, 27(23), 8602.
Pistelli, L., Ascrizzi, R., Giuliani, C., Cervelli, C., Ruffoni, B., Princi, E., ... & Pistelli, L. (2020). Growing basil in the underwater biospheres of Nemo's Garden®: Phytochemical, physiological and micromorphological analyses. Scientia Horticulturae, 259, 108851.
http://www.nemosgarden.com/