seaweed extract for cannabis

Why Seaweed Is A Superfood For Cannabis Plants

Seaweed is cheap and easy to access for those living near the ocean. The life form is full of beneficial nutrients that will help your cannabis plants survive and thrive.

The use of high-quality nutrient sources is key during the cannabis grow cycle. Keeping an accurate flow of nutrition into the soil of your plants will ensure maximum health, vitality, and yield. It will mean that you avoid the risk of your plants encountering deficiencies, which will wind up damaging their health, slowing their growth, and reducing the prized end result of the harvest.

There are numerous options to select when it comes to nutrients for your crops, from waste food items all the way to commercial product lines. Well, we want to introduce the idea of using a unique yet effective choice of nutrients: seaweed.

As it happens, seaweed is absolutely crammed with beneficial nutrients that your cannabis plants will happily utilise to achieve optimum health, size, and growth. Seaweed is available to growers in numerous forms. The first form is easily the cheapest and most accessible for those who live near the coast. We’re talking about fresh seaweed, which can simply be harvested during a trip to the beach.


Many different types of seaweed have been employed all over the world for centuries in agricultural settings. Fresh seaweed contains a plethora of major and minor plant nutrients and trace minerals that it absorbs from the ocean. These include minerals such as sulphur, magnesium, boron, and calcium.

When ground up and incorporated into meal, seaweed may also contain beneficial vitamins such as A, C, B12, K, and E. Seaweed also contains substances that regulate plant growth, contributing to rapid and explosive development of crops.

Seaweed also helps soil to retain moisture and may reduce the amount you have to water your plants. When used as a mulch, seaweed may also reduce or eliminate the need to weed your garden, acting as barrier against the formation of intrusive plants.

It’s not only weeds that seaweed offers defence against; the lifeform also produces compounds that are effective against certain fungi, viruses, and bacteria. It’s almost like a medicine for your cannabis plants. As well as fighting off bad bacteria, seaweed can help to condition the soil and encourage the growth of beneficial bacteria.


Kelp is a type of algae seaweed that is particularly nutritious. There are around 23 different species of kelp that grow around the world. They form underwater kelp forests and grow in shallow, nutrient-rich waters. It’s this environment that makes kelp so beneficial to cannabis and other plants. The seaweed absorbs a vast array of ocean minerals which are dispersed into the soil when added as a fertiliser.

Kelp is capable of meeting most of the nutritional needs of the cannabis plant. Overall, it contains over 60 trace elements essential to the growth of the herb. These include iron, manganese, cobalt, zinc, and molybdenum. Many of these minerals are crucial micronutrients for cannabis. Although only required in small quantities, they fulfil vital physiological processes. For example, iron is necessary for energy production and the formation of the green pigment chlorophyll. Additionally, the micronutrient manganese is used by plants during photosynthesis, respiration, and nitrogen assimilation. Kelp is a superb source of organic nutrients to fuel these processes.

Kelp offers more than just nutrients. The seaweed also helps to stimulate beneficial microorganisms in the soil. These life forms form synergistic relationships with plants. In return for sugary exudates, they break down organic matter and help their plant allies access vital nutrients.

Kelp also helps to regulate soil pH, an essential variable during cannabis cultivation. Cannabis needs a soil pH of between 6–7 to grow correctly. The roots won’t be able to effectively uptake nutrients if the pH fluctuates above or below this sweet spot. Kelp’s vast supply of beneficial molecules also means the seaweed helps plants during the germination process and allows them to develop sturdy and robust stems and branches.


Kelp is available in several forms. Growers can add liquid kelp during watering. Simply pour around two teaspoons into five litres of water. Liquid kelp also boasts the presence of growth hormones that promote the development of healthy roots.

Kelp meal is a second form of the supplement. Add it to the soil at a volume of 0.5kg/9m². It will take around four months for the nutrients to release into the soil, so add it well before the outdoor growing season commences.

Finally, kelp powder can be used to make a foliar spray as the nutrients are directly available for absorption. Add half a teaspoon of powder into 5 litres of water and spray away!


Considering you live relatively close to the ocean, the easiest way to obtain seaweed is to forage it for yourself. This eliminates any cost and is a perfect chance to go and immerse yourself in nature for a while.

Before you do so though, it’s worth doing some quick research into the area you plan to forage at. Taking seaweed from a polluted area is not advised, as this may introduce undesirable substances into your garden. It’s also worth checking if there are any restrictions in place that prohibit taking seaweed from the local environment.

If you’re in the clear, head to the beach with a bag and collect a bounty. Use a species guide to identify what you take. Kelp is a very popular choice among gardeners, along with knotted wrack.

Once harvested, head home and give your bounty a wash. Next, it’s time to decide what to do with it.


Most seaweeds can be directly applied to the soil via mulching and will break down quite fast. Simply layer seaweed over the top of your soil and let nature takes its course.


Given all of the nutritional benefits, it’s quite obvious that seaweed will make an excellent addition to any compost bin. Be sure to mix in the seaweed well with the rest of the materials to prevent any slime from reducing airflow.


Liquid fertiliser is very easy to make and extremely easy to apply to plants. It can also be made highly concentrated, so less volume needs to be used at a time. Simply add your seaweed and other composting material into a barrel with a small amount of water, and wait for it to break down over the course of several months.

Once ready, it can be sprayed onto your crops to help defend against disease and to assist during the flowering phase.

Seaweed is absolutely loaded with minerals, vitamins, and growth regulators that help protect plants against disease, speed their growth, and maximise yields.

Top 5 Reasons Why You Need Kelp in your Cannabis Grow

Effect of Kelp on Plant Growth

Kelp is an array of massive brown algae (seaweed) that grows underwater and on rocky shores. Kelp is located in regions of the world with cold waters.

The benefits of marine kelp extract to plants have been identified through their active ingredients which include richly available plant hormones and beneficial trace elements (iron, copper, zinc, manganese, calcium, magnesium, sodium, sulfur and others).

The combination of these active ingredients makes the use of kelp extract an effective fertilizer and biological stimulant for enhancing better plant growth and development. The kelp extract from brown kelp Ascophyllum nodosum accumulated in mineral waters is known to be the best. Ascophyllum nodosum by nature develops within the littoral zone and is subjected to severe temperatures and varying intensities of sunlight. Therefore, it is exceptionally abundant in phytohormones (auxin, cytokinin, and gibberellin) and phytosanitary agents, and when subjected to stringent quality control methodologies, they become stable products.

Hormones are naturally found in plants to direct and regulate growth, development and other physiological processes in the plant. They are produced in a single part of the plant and transmitted to the other part of the plant, which is the site of action to cause physiological changes. Auxins are produced in leaves of plants after which is dispatched to roots and growing tips. Cytokines are supplied in the root and transmitted to leaflets and growth tips.

Some of the effects of kelp on plant growth are as follows:

  1. Bio-stimulation of germination and growth in plant

Kelp contains almost all micronutrients in the readily available form as well as plant hormones; all that encourages plant growth.

Kelp is also rich in carbohydrates that serve as plant material and also a source of food and energy for useful microorganisms in the root zone. The cytokine hormone mobilizes nutrients in plant leaves to improve the chlorophyll content, increase leaves, nodes, and buds. Also, kelp effectively supplements any nutrient deficiency and promotes additional budding sites when applied as a foliar spray after flowering begins during the flowering period.

Kelp additionally contains gibberellins with gibberane structures which are known for their impacts on stem elongation, parthenocarpy, bolting and flowering and at the same time essential for breaking seed dominance to induce germination. These effects are achieved when seeds are predominantly treated before planting by soaking seeds in liquid kelp extract.

  1. Increased Plant Immunity

The kelp extract facilitates the absorption of nutrients and provides powerful plant hormones; this makes the plants healthier and more resistant to diseases. Kelp also contains natural antibiotic properties that can help eliminate harmful bacteria. These features also make seaweed good fertilizer, where antibiotic properties can help protect the leaves from infection and discourage pests. Seaweed extracts are particularly rich in cytokines. Cytokinins stimulate rapid cell division and production of new cell walls, so cytokines are particularly crucial for further growth. If cytokinin is used during vegetative growth, the plants will grow faster with stronger cell walls.

  1. Expanded and Healthy Root Zone

Cytokines work together with other herbal hormones. If, for example, they apply cytokinin during root formation, the cytokines will stimulate the division of multiple root cells. Kelp solutions applied directly to the root zone enhances root, health, and vitality. Starch molecules similar to sponges found in kelp can retain water near plant roots for a long time, making moisture available to roots without saturation. These starches also help to enrich the soil by feeding beneficial microorganisms, bacteria, and fungi. Kelp also acts as a form of soil remediation by improving the overall structure of the soil.

  1. Fortifies Plant Development

Another essential feature of kelp is its rich concentration of vitamins; especially in the form of vitamin B. Vitamins provides the plants the power and energy needed to progress under the stress of accelerated growth rates. These powerful B vitamins can be particularly useful in cloning to reduce the mortality rate of vulnerable young plants.

  1. Increased Yields

The most prominent visual effects of kelp fertilizer will be visible at harvest time. Rich content of stimulants, enzymes, and nutrients will generate more abundant flowers, fruit, and vegetables. Cytokinins applied just before flowering aid the formation of more lateral buds which will help in the overall yield and quality of the budding plants.

Kelp as an Ingredient in our formulas

The wonderful effects of kelp on plant growth are evident, with many studies publicly attributing to their effectiveness in agricultural applications. With this understanding, we’ve formulated products with kelp in them already to help in maximizing plant growth while saving the growers the expense of having to buy a separate kelp additive. Some of our products you can find kelp in are: Omega Grow and Omega Bloom formulations, Beta Balls a microbial booster and trace mineral granule, as well as in MycoRhize, our 12 species mycorrhizae inoculum. By using these products and incorporating them into your regiment, you won’t have to go out and buy kelp separately since these formulas utilize large amounts of kelp in them already.

Ali, Nerissa, et al. “The Effect of Ascophyllum Nodosum Extract on the Growth, Yield and Fruit Quality of Tomato Grown under Tropical Conditions.” SpringerLink, Springer, Dordrecht, 12 May 2015,

“Plant Hormones and Their Role in Plant Growth and Development.” 1987.

Thorsen, Maja K., et al. “Kelp (Laminaria Digitata) Increases Germination and Affects Rooting and Plant Vigour in Crops and Native Plants from an Arable Grassland in the Outer Hebrides, Scotland.” SpringerLink, Springer, Dordrecht, 26 Feb. 2010,

Zheng, Shiyan, et al. “Effect of Kelp Waste Extracts on the Growth and Development of Pakchoi (Brassica Chinensis L.).” Scientific Reports, no. 1, 2016.

Effect of Kelp on Plant Growth Kelp is an array of massive brown algae (seaweed) that grows underwater and on rocky shores. Kelp is located in regions of the world with cold waters. The benefits of marine kelp extract to plants have been identified through their active ingredients which include richly available plant h