University of Southern California Sea Grant Program

Help with Kelp

Kelp is very good at growing - the giant kelp off the coast of California can grow up to 1 or 2 feet per day!! Like land plants, kelp uses energy from sunlight to make its own food. This process is called photosynthesis. Sunlight is captured by the plant and the energy particles in sunlight (photons) are used to drive a chemical reaction that produces sugar. This sugar is the food for the plant. In a land plant, usually only the leaves are capable of photosynthesis, but all parts of the kelp plant can photosynthesize. A kelp plant starts out as a single flat blade attached to the bottom and then grows into a mature plant. Giant kelp can get to be over 150 feet long! Kelp sometimes grows in dense patches of many individual kelp plants - these dense patches are called kelp forests, because they resemble a forest of trees.