A greenhouse underwater sounds both implausible and impractical. But why not? The temperature doesn’t fluctuate, so there’s no frost. Aphids can’t get anywhere near the plants, the pumped-in atmosphere is CO2-rich. And the plants — apparently–love it.
The Orto di Nemo project–Nemo’s Garden, as it’s called in English–resides 30 feet under the waves, off the Noli Coast in in Italy. Head “gardener” Sergio Gabriel and team have tethered bubbles to the ocean floor and filled them with air. These open-based bubbles work like diving bells, and look like something straight out of a Jules Verne novel. A shelf runs around the inside of the dome, and on that shelf sit plant pots. Currently Gabriel, president of the Ocean Reef Group, is growing basil, strawberries and lettuce, just like you’d grow it on your kitchen window-ledge.
Unlike your basil plants, though, these were sealed to protect them from the seawater, before being taken to their watery homes by divers. The greenhouses enjoy a placid environment, so they could work off the coast of even the most arid of lands, and being underwater actually brings other advantages. For instance, the open base of the bell means that there is a large water surface at the bottom of the bubble, and natural evaporation keeps the garden’s environment humid.
That’s not to say that these biospheres are isolated from the surrounding ocean. Gabriel says that crabs have already climbed up the tether ropes and inside the greenhouses to take a look round, and jellyfish like to shelter underneath. Combined with the herbs in the garden, that sounds like a delicious combination. You can even keep an eye out for visitors on the live video feeds.
The plants thrive because of high carbon-dioxide levels, which they love. In fact, these undersea plants grow much faster than they would up on dry land. Sergio’s son Luca Gamberini told the Washington Post that “We completely lost the crops four times, but it didn’t really matter because we have such great growth rates.”
Individual biospheres tended by professional divers are clearly not a practical way to farm food, but the design could be scaled up. Accidents could prove to be catastrophic, with a toxic environment pressing in on the walls at all times, but no more catastrophic than losing entire harvests to frosts or drought.