This is insane! There's an Italian farm that's entirely underwater and you have to scuba to get there! It's called Nemo's Garden and the Ocean Reef Group created it. Apparently, the farmer had his crops on land, but the cold temperatures were killing them.
Under the water in those domes, the temperature is pretty constant, allowing the plants to grow efficiently.
Maybe this underwater farm thing will become more and more common. Anyways, check the video out below: