Marine Kelp is a type of Herb. It grows in the Aquatic Depths on naturally occuring Mossy Marine Rock, where it can be collected with any weapon or tool. It can also be found in Depth Chests or extractinated from Brackish Clumps. It can be planted on Mossy Marine Rock and Planter Boxes using Marine Kelp Seeds. It does not require water to grow, nor does it die if submerged in water. When fully grown, it will drop more Marine Kelp and 1-2 Marine Kelp Seeds.