Using kelp for plants can be done in three ways – as mulch, as fertilizer and as compost. Plants love kelp and kelp extracts, as they are very nutritious.Kelp for Plants

Thankfully, kelp is super easy to use in the garden and you do not need any special skills to apply it. Read this article to learn popular methods to use this seaweed in your garden.

How To Use Kelp as Mulch for Plants in 3 Steps?

To use kelp as mulch for plants in three steps you need to collect kelp from a nearby beach or any body of water, spread the kelp over your garden soil and reapply as needed. Mulch helps to protect roots and keep water from disappearing.

1. Collect Kelp From a Nearby Beach

You can collect kelp from a nearby beach, canal, or any body of water. While you can use any type of seaweed as mulch, kelp is the most nutritious and beneficial one for your garden. Before you go searching for and collecting kelp, check your local laws if you can collect kelp and other types of seaweed. Remember to rinse it before use.Collect Kelp From a Nearby Beach

2. Spread the Kelp Over Your Garden Soil

It is time to mulch your garden. Within 36 hours after gathering kelp from the beach, spread kelp all over your garden so that it is at least 4-6 inches deep. Spread it religiously. However, leave some inches of space around the stems of your plant so that your plants’ roots can have access to air.

Also, do not spread kelp on the walkway of your garden, as it can become slippery. Don’t worry, as kelp starts decomposing in your garden, every part of the garden will get nutrients.

3. Reapply the Kelp in Your Garden Weekly

Just 4-6 inches of kelp isn’t enough to significantly enrich your garden. As a type of seaweed, kelp decomposes quickly. Therefore, continue topping the kelp in your garden weekly. Do this for four to six weeks until you see a significant color change in your garden soil.

When using kelp as mulch for your garden, remember to water it and your plants regularly. This can help speed up the process of decomposition. It can also help transfer nutrients from the seaweed to the soil and roots of your plants.

How To Use Kelp as Fertilizer for Plants in 5 Steps?

To use kelp as fertilizer for plants in five steps you need to prepare the kelp, soak it in water and check the mixture on a weekly basis. Once it is ready you can apply it directly to the soil or use as a foliar spray.

1. Prepare the Kelp

After collecting the natural kelp meal from beaches, you have to prepare it first before you use it as a fertilizer. Using running water, rinse the kelp so that there’s no dirt attached to it. Though not compulsory, you can shred the kelp into bits to speed up the process. The smaller objects are, the quicker they can break down to become fertilizer.Prepare the Kelp

2. Soak the Kelp in Water

When your natural kelp meal is ready for use as a fertilizer, soak it in water. There’s no definite ratio for soaking kelp in water. Just keep in mind that the more water you use, the less concentrated the fertilizer will be. If you’d love to use the fertilizer without first diluting it for your plants, mix one-part kelp and nine-parts water.

While simply leaving the seaweed in water is enough to make fertilizer, you can make a better product by using aerators. Using aerators to aerate the soaked kelp will help fungi and other decomposing microbes to break down the kelp faster. It will also ensure that the fertilizer is a product of decomposing microbes, not fermenting microbes.

3. Check the Fertilizer Weekly

Just as when making an organic fertilizer with other products, you have to check your kelp meal fertilizer weekly. How far dissolved is the kelp? Do you notice any color change in the water? If so, it means that the kelp is dissolving.

Is there any foul smell? If so, mix the kelp and properly aerate the water. Properly aerating the liquid kelp will prevent a foul smell.

4. Apply Directly to the Soil

At least one month after soaking the kelp in oxygen-rich water, the fertilizer should be ready. Kelp fertilizer benefits are numerous and you can use the product just the way you use a regular fertilizer. Just remember that this fertilizer is richer in nitrogen, therefore, you best use it to start your plants or boost leaf production.

5. Use as Foliar Spray

The liquid kelp benefits for plants, as you already know, are numerous. You can make a kelp foliar spray with the fertilizer. All you have to do is get a spray bottle, fill it with kelp fertilizer, and spray it directly on the leaves of your plants. If the fertilizer looks too thick, dark, or concentrated, dilute it before spraying it on your plants.

How to Compost Kelp for Plants in 5 Steps?

To compost kelp for plants in five steps you need to first of all add the kelp to your compost pile, then add other needed ingredients to the pile. You should mix and turn the compost pile regularly, check if it is ready and then use it!

1. Throw Kelp Into Your Compost Pile

When you get kelp from your local waterway, you can simply throw it into the compost pile. So long as you collect the kelp from a natural non-polluted source, you don’t have to wash it. What you consider as dirt attached to the kelp could also be beneficial to the compost pile.Throw Kelp Into Your Compost Pile

2. Add Other Needed Ingredients to the Pile

Unlike mulching or making fertilizer, you cannot make compost with only kelp. The reason is that compost is made of one-part nitrogenous materials and four-part carbon-rich materials. Fungi and other decomposing microbes use energy from carbon to decompose nitrogen and other nutrients.

Therefore, even if kelp is the only nitrogen-rich material you have in your pile, you must add some carbon-rich products. These products are usually dry and brown. Some examples are paper, dry leaves, hay, etc. Add them in the right proportions (i.e., 4:1).

3. Mix and Turn the Compost Pile Regularly

You have to properly mix and turn the compost pile so that the ingredients are evenly spread across the pile. Mixing and turning the pile also helps oxygen to get into every part, as you want only decomposition (not fermentation) to take place in the pile.Mix and Turn the Compost Pile Regularly

If the pile becomes stinky, you are not mixing and turning it as regularly as you should. If this work seems too difficult for you, consider getting a tumbling composter so that you can easily turn it.

4. Check if the Compost Pile Is Ready To Use

A compost pile that is ready to use smells earthy and feels somewhat gritty when you rub it between your fingers. Dipping your fingers close to the core of the pile is the best way to tell if the pile is ready.

An active compost pile (i.e., one that isn’t ready) has a hot core. It is hot because of the decomposing microbes. The temperature in the core of a compost pile that is ready for use, however, is not significantly higher than the temperature outside the pile.

5. Apply the Kelp Compost to the Garden

When the compost pile is ready for use, use it in your garden. You can use it as mulch, a starter for your seeds, and even fertilizer for your plants. If you want to mix it with the soil, mix it two or more weeks before you plant your crops.


Now, you know how to make kelp fertilizer and other products for your plants, right? Before you go collecting some kelp, remember these points:

  • You can simply use kelp as mulch in your garden. It will still release nutrients for your plants.
  • To make a foliar fertilizer for your plants, just make a liquid fertilizer out of kelp and spray it on your plants.
  • Spray the seaweed fertilizer directly on the soil so that the roots of your plants can benefit from kelp.
  • When making fertilizer with kelp, ensure that the seaweed dissolves completely before you use the fertilizer.
  • The best kelp fertilizer is compost made of kelp.

Kelp is truly a versatile product, so use it in your garden. It does not matter what you want to use it for, your plants will surely benefit.

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