Difference Between Kelp and Seaweed

Seaweed uses light made by the Sun, and Carbon Dioxide to grow while Kelp uses nutrients provided by the deeper-moving seawater to grow. They both can form many shapes colors and flavors but Kelp is considered a Super Food to eat by health enthusiasts and looks the same as Seaweed to the average person. What’s the difference between Kelp and Seaweed?

  • Kelp is a big type of Seaweed
  • Grows together in a “forest” in deep Saltwater
  • Provides Bio Habitat
  • Anchors to seafloor
  • Uses H2O movement to absorb nutrients
  • High in Iodine & nutrients


  • Seaweed has 10,000 species
  • In Fresh & Saltwater
  • Uses sunlight & Carbon Dioxide.
  • High in calcium & minerals
  • Used in Industries


Seaweed can be used to describe many different marine-based species of plants and algae in the water. In fact, Sea kelp is a group derived from Seaweed. How are they different and which one contributes more to us and the environment is a matter of opinion but both are very special maritime plants.


Difference Between Kelp and Seaweed


The main colors of Seaweed are red, green, and brown which can be the names of the groups that they are broken down into. With strange names like egg-wrack or knotted-wrack. With its Latin name Ascophyllum nodosum, this is a common Brown Seaweed that can be found laying on the Beach at low tide. Then at high tide disappears again until the next tide change.

These extremes of conditions from wet to dry, with different UV levels, and different predators, twice a day every day, are thought to contribute to the specific antioxidants and other nutrients found in chosen species of seaweed. Sea Kelp is considered a Brown type of Seaweed but can come in a variety of colors.

Seaweed can grow in an assortment of sizes while Kelp will always grow bigger. Color has a direct effect on how much light seaweed absorbs via photosynthesis, which decides how close to the ocean’s surface it grows. seaweed can grow almost anywhere in oceans lakes and rivers while Kelp only grows in Saltwater.

Sea kelp needs nutrient-rich waters because of their bigger size, and there needs to be at least a small amount of movement in the water to ensure a regulated supply of nutrients that are available to it. Giant kelp is a perennial it lives for seven years.

Both Seaweed and Kelp both have some particular characteristics that are unique to plants that grow on land. Seaweeds have what are called holdfasts instead of roots. They hold the plant in place rather than absorb nutrients as a normal plant does on land.

Sea Kelp can easily survive without these holdfasts carried off on ships and floating on tides. Sea Kelp one of the largest types of Sea Weeds will fix itself onto a single spot. They attach themselves to other Kelp and form large groups of bushes. These lead to types of forests and then become their own ecosystems. They can be fully functional and provide food and shelter for marine wildlife. It will also act as an environment.

Where is Kelp Found


Kelp Forest grows all along the west coast of America predominantly on the Pacific Coast, from Alaska and Canada to the waters of Baja California.  They are dominated by two canopy-forming, brown macroalgae species, giant kelp (Macrocystis pyrifera) and bull kelp (Nereocystis leutkeana).

Giant Kelp is more populated and recognized forms the more southern kelp forests, from the southern Channel Islands, California to northwestern Baja. Our national marine sanctuaries harbor kelp forests. Giant kelp inhabits the Channel Islands National Marine Sanctuary as well as the Monterey Bay National Marine Sanctuary, where giant kelp and bull kelp coexist. In the more northern Greater Farallones and Olympic Coast National Marine Sanctuaries, kelp forests are comprised of predominantly bull kelp.

The Kelp grows along rocky coastlines at depths of 6 to 90 ft. deep.




They can grow successfully in upwelling water that is cool and nutrient-full. There is a negative growth rate in the summer months when warmer water enters southern California where giant kelp forests deteriorate in those months.

Along with the Central California Coast, different types of Kelp (Giant & Bull) compete for sunlight and the Giant Kelp usually wins. California sea lions, harbor seals, sea otters, and whales often feed in the kelp forest during the day or escape storms or predators in the shelter of kelp.

On rare occasions, gray whales have been spotted seeking refuge in kelp forests from predatory killer whales. All larger marine life, including birds and mammals, may retreat to kelp during storms or high-wave activity because the kelp helps to weaken currents and waves.

Where is Seaweed Found


Some seaweeds are microscopic, such as the phytoplankton that lives suspended in the water column and provides the base for most marine food chains. Some are enormous, But most Seaweed that we are used to seeing just washes up on the beach just about anywhere. Seaweed can live in any marine environment. Just like terrestrial plants, Seaweed must live near the surface of the water to absorb sunlight for photosynthesis and an abundance of Carbon Dioxide.

China and Indonesia produce the largest amount of Seaweed.  Seaweed is a hardy plant and does require you to plant and harvest, but does very little in between. It needs no fertilizing, no weeding, no watering, and it has very few enemies in the form of pests or diseases. It gets all it needs from the environment around it and, under optimal conditions, can grow almost six inches a day. It’s healthful for people, and it actually leaves the environment better than it finds it.


Kelp Seaweed Benefits


Around the world, Seaweed and Kelp are considered healthy food. They have been used throughout history even as medicines. Each one of the thousands of species has different nutritional benefits that are unique to other foods.

Compare the government’s nutritional data for kelp which is a subgroup of Seaweed with the data for a nutritious terrestrial green spinach and you find that, gram for gram, the seaweed isn’t as nutrition-dense but is still a perfectly respectable vegetable and an excellent source of iron, folate, and vitamin K.

Some scientists speculate that seaweed has benefits beyond the standard-issue list of nutrients and that more-obscure compounds might confer special advantages. Proteins, polyphenols, and polysaccharides might help fight viruses, cancer, or obesity. Alginate, a kind of fiber in seaweed, appears to block fat absorption. Seaweed is very high in iodine which is needed in your regular diet. Seaweed has the recommended amount in a small amount. Too much Iodine is harmful to the Thyroid.

So there are some health benefits for each one:  1 Cup of Kelp 

  • One Cup of Kelp contains about 34 calories
  • Each Cup contains grams of total carbohydrates, including 1 gram of dietary fiber.
  • Kelp also contains 1.4 grams of protein per serving.
  • Kelp provides more calcium per serving than other seaweeds.
  • It boasts 134 milligrams of calcium per 1 cup or 13 percent of the recommended daily intake established by the Institute of Medicine.
  • Kelp contains a moderate amount of iron – 2.3 milligrams, or approximately 29 and 13 percent of the recommended daily intakes for men and women
  • Kelp serves as a superior source of vitamin K compared to other seaweeds. Kelp boasts a vitamin K content of 53 micrograms per cup-Just 1 cup of kelp provides 42 percent of the daily intake for men and 59 percent for women.

Kelp contains significant levels of tryptophan, threonine, isoleucine, methionine, cysteine, and valine. Kelp also contains lower levels of leucine, lysine, phenylalanine, tyrosine, and histidine. Kelp has the capacity to absorb many trace minerals from seawater. You can also obtain moderate levels of vitamins A, E, and C, thiamin, riboflavin, niacin, and pantothenic acid. Kelp is a source of 70 vitamins and minerals.

There are a few health benefits that Seaweed holds over Kelp some that equal:  1 Cup of Seaweed

  • One Cup of Seaweed contains a similar amount
  • Some Seaweed contains similar amounts of protein
  • Seaweed contains about 1/2 the amount
  • Irish Moss Seaweed contains 3 x the amount of iron as Kelp
  • Kelp is a huge source of Vitamin K well over Seaweed

Adding seaweed to your diet also helps you modestly boost your intake of calcium and essential minerals. Most of your body’s calcium goes toward keeping your bones and teeth strong.


How do you Propagate Plants from Cuttings in water?

  • Snip cuttings from the plant.
  • Cut 1/4″ below the node at a 45° angle with a clean knife or scissors.
  • Stick cutting in a clean glass
  • Pour tepid room H2O to cover nodes
  • Change H2O every 3-5 days
  • Wait till the roots grow(this can take weeks to months, depending on the plant)
  • Once roots are 2-5″ Pot in soil…………………………………………………………………………………………………………… Read more

Kelp vs Seaweed: Fertilizer-Brown-Sea Gardening


Organic Kelp Fertilizer is valued for its Micro and Macronutrients like phosphorous, nitrogen, and potassium building blocks. It comes in a liquid form too, that is used to super treat nutrient-deficient soils.

Kelp is a nutrient-rich seaweed often hailed as a Superfood because it contains vitamins A, B-12, B-6, C, copper, iron, magnesium, manganese, niacin, riboflavin, thiamin, and zinc giving it more calcium than kale and collard greens.

Seaweed is high in iron content and can offset Anemia and other conditions like Attention Deficit Deficiency. Seaweed is also a good source of soluble fiber, omega-3s, and antioxidants.

Carrageenan and Agar extracted from red seaweed is a thickening agent used in puddings, chocolate milk, chewing gum, jams, and jellies. Algin or alginates from brown seaweed and agar from red seaweed are widely used in bakery products, candies, dairy products, salad dressings, ice creams, chewing gum, creams, and jellies, as well as in processing meats, sausages, and fish and in clarifying beers and wines. Used in Science Labs for Petri dishes or test tubes and cultured for study.


Why is the Water Hyacinth Invasive?

Causes H2O loss & a negative impact on the water balance
Clogs rivers & canals
Interferes with hydroelectric Dams
Hampers fishing
Hampers navigation
Affects H2O control & use for agricultural purposes
Displaces native species
Increased sedimentation caused by roots
Increases shading caused by the leaves .……………………………………………………………………….. Read more



Seaweed is used in the Cosmetic Industry used in facial masks and skin products body gels and shampoos, toothpaste, and shaving products.

Carrageenan and algins are used in pharmaceuticals as binders, stabilizers, emulsifiers, and for creating molds. The dental industry also uses them in molding preparations. They are used in cough medicines and other products for gastric reflux control.

Algins from Brown Seaweed are present in a variety of products, including paints, pigments, dyes, and finishes. They are used in fiber manufacturers such as paper, cardboard, filters, and textiles. Charcoal briquettes are bound together with them. Algins are manufactured in explosives, pesticides, and fire retardants, including fire extinguishers. It’s also made into Soda ash—or as we know it sodium carbonate

Kelp has a huge environmental responsibility that plays out every day besides the vitamins and nutrients it can filter from the sea and add to the food we eat. The kelp forest is an extremely biologically productive habitat for a huge range of sea creatures including fish, urchins, sea otters, sea lions, and even some whales. Because of this, kelp forests are critical for the fishing and recreation industries. Kelp forests maintain a delicate balance in order to support a diverse range of sea creatures.

*There is no doubt that Seaweed and Kelp from specific places around the world are becoming more an important source for health issues for everything from arthritis to regulating blood pressure. Kelp and Seaweed products can be added to your favorite foods as dried flakes that can be like here This is Seaweed – a brainchild put together by Paul O Connor a Marine Biologist from Ireland who wanted to share his knowledge of the Nutrient-rich Atlantic Ocean.



Where is Wasabi Grown?

Wasabi is grown in versions of its natural habitat in three regions of Japan:
Izu peninsula, Nagano Prefecture, & Iwate prefecture
At sea levels of 1300-2500 meters
In Temp. 8° to 20° C
High in the Southern Mountains
On isolated paths
In flooded gravel streambeds H20 percolated through volcanic rock ……………………………………………………………………….. Read more



JimGalloway Author/Editor



References: Seaweeds of the North-east Atlantic


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