A kelp farm can be planted by a terraforming unit or unity pod and increases the nutrient production of an ocean square by +2.
Kelp farms can be planted on ocean shelf squares (depth less than 1000m). With the discovery of Adv. Ecological Engineering, aquatic factions such as the Nautilus Pirates can also plant Kelp Farms on ocean and ocean trench squares.
A Kelp farm will sometimes expand into adjacent squares, even driving out native sea fungus in the process.