What Is the Main Difference Between Seaweed and Kelp?

What Is the Main Difference Between Seaweed and Kelp?

People tend to use the terms “seaweed” and “kelp” interchangeably, but they’re drastically different. Summing up an entire population of sea vegetables with those two words may seem easy. But what is the main difference between seaweed and kelp?

The demand for seaweed and kelp is growing immensely. Experts are now putting these ocean-grown vegetables in toothpaste, ice cream, and even your beer! They’re quite possibly the most sustainable foods on the planet due to their low-maintenance growth. Let’s explore their unique traits and how they’re alike yet different.


Seaweed is in the algae family, and kelp is essentially the largest subgroup of seaweed. Algae is a group of aquatic organisms that are mainly photosynthetic and nucleus bearing. In other words, they’re not your average plant: they lack stems, roots, and other common plant characteristics. The beauty of algae is that it absorbs the atmosphere’s carbon dioxide and produces approximately 50% of oxygen here on Earth.

Ocean farmers grow kelp vertically by wrapping tiny kelp plants grown on string around nautical rope, which hangs below the water’s surface from buoys.


Typically, kelp is what you see along the shore when you’re walking on the beach. Kelp tends to be longer than seaweed. Additionally, you may notice air bladders on kelp, which keep it afloat to access the sunlight it needs for photosynthesis. Kelp is known to grow a bit further into the ocean—many kelp forests extend from the sea floor to the surface!

Seaweed and kelp range in color, from red and brown to green. The coloring depends on how much oxygen the plant receives and other factors, including pigments that capture light for photosynthesis.


Green algae contain chlorophyll and store it in their cells after photosynthesizing. This produces the green color. Many people compare green algae to sea lettuce.


Red algae also contain chlorophyll, but they also have red and blue pigments such phycoerythrin, phycocyanin, and allophycocyanin. These substances tend to conceal the green color, producing red hues.


Brown algae get their color from carotenoids, another type of pigment developed from the photosynthesis process. When algae are brown, that means their chlorophyll captured the most light, which is beneficial in darker areas of the ocean.

Seaweed and kelp are both extremely beneficial to our health, and we can utilize them in our diets due to their high volume of vitamins and minerals. Understanding the main difference between seaweed and kelp is crucial to determining which one will benefit specific health conditions. If you’re hoping to add some extra flavor to your meals, try adding organic wakame seaweed. Check out our Recipes page for tasty ideas!