Everyone knows what kelp is, but for us gardeners kelp holds a special place in our green hearts...or it should!

Kelp fertilizer is one of the best supplements you can use in your garden for a variety of reasons.

What is Kelp Fertilizer?

Liquid kelp fertilizer is a natural alternative to artificial fertilizers used for growing plants but without any by-products or environmentally damaging chemicals. The seaweed used to produce kelp fertilizer is sustainable and it can be harvested in a way that is safe for the environment, given that kelp has a particular cell structure that enables it to grow up to three feet per day.​

It usually comes in a concentrate that is to be diluted depending on the plant that it is being applied to. For instance, the fertilizer that would be applied to a lawn (not that I'm an advocate for lawns) would be much more diluted than of that applied to a houseplant.​

Kelp fertilizer is so effective and reliable that it's used on professional golf courses and football fields all across the country. Its effects are seen quickly and a little bit of the concentrated fertilizer goes a long way.

How is Kelp Fertilizer Made?​

A bunch of ascophyllum nodosum kelp, the most commonly harvested for kelp fertilizer.

A bunch of ascophyllum nodosum kelp, the most commonly harvested for kelp fertilizer. source

The most commonly harvested kelp is the Ascophyllum Nodosum which is found in the Atlantic Ocean in the cold northern waters. The kelp is collected and then washed with fresh water to remove salt, and then it is dried of the water, and turned into a powder.

It must be at peak cytokinin levels to be effective as a fertilizer. Cytokinins are the growth hormones which enable cell division and turnover rates for rapid plant growth and development.​

What are the Benefits of Kelp Fertilizer?​

Liquid kelp can benefit your plants no matter what stage of life the plant is in. Studies have found that soaking seeds in seaweed extract reduces transplant shock, and benefits the roots to grow at a more rapid rate and with more mass, and the plant's overall survival rate becomes higher.​

Liquid kelp fertilizer appears to be a miracle product when used on almost any plant:

  • Many fruits become sweeter
  • Veggies are less prone to softening and often grow larger
  • Increases flower production on flowering plants
  • Increases overall plant resilience to disease
  • Cut flowers stay fresh longer
  • Encourages root growth, both in rate and root mass
  • Fruits and vegetables survive longer post-harvest if treated with seaweed fertilizer pre-harvest

Using kelp for plants is not only a good idea because it's a natural fertilizer, thus providing nutrition to the plant, but it also encourages your plants to more effectively draw nutrients from the soil in general. This means that your plants are more efficient growing machines.

How to Use Liquid Kelp​ in Your Garden

Many chemical fertilizers you'd buy in stores tell you to to distribute directly onto the soil. However, most plants absorb their nutrients through their leaves, thus benefiting more from a foliar application, or spraying the fertilizer directly on the leaves.​

Kelp fertilizer is typically applied to the leaves in a diluted mixture by a spray bottle, and as the plant absorbs the sunlight, it will absorb the foliar application as well. While you can apply a kelp extract directly to your soil or growing medium, applying directly to the leaves has proven to be up to twenty times more effective.​

How a surfactant helps the application of your kelp fertilizer foliar spray.

How a surfactant helps the application of your kelp fertilizer foliar spray. source

It is best to use a non-ionic surfactant prior to treating with the fertilizer. That's just a fancy word for a substance that reduces the surface tension of a liquid. This means that your foliar application of kelp fertilizer won't form water beads and simply roll off of your plant's leaves. Instead, it will saturate the entire leaf surface and increase nutrient absorption.

Liquid kelp can also be used with hydroponic systems to preserve the life of seedlings. The kelp extract ensures that the water bed is fit for growing before it is able to host the growth-necessary bacteria which takes roughly 4-6 weeks to form.

Should you find your plants beginning to wilt or lose their color, adding the recommended amount of kelp extract will improve the health and appearance of the plants within the day.​

Where to Buy Kelp Fertilizer

Because of kelp fertilizer's rapidly growing popularity, many home and garden stores carry a variety of brands. Fertilizer can also be bought online with some of the top rated products on Amazon being

You may also want to pick up these complementary products to help with your foliar application:

There are truly no downsides to using a kelp fertilizer. The product is eco-friendly, sustainably sourced, fairly easy to use, cost efficient, and yields consistent and amazing results for your garden, no matter how big or small.

Of course, you can also make your own kelp fertilizer if you live near the ocean and want to spend the time. Here's a good video I found on going that route: