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A Complete Seaweed Fertiliser Guide

25th June

A complete seaweed fertiliser guide covering the frequently asked questions about one of the most popular plant feeds among gardeners.


Jump to section:

What is a Seaweed Fertiliser?  •  Are Seaweed Fertilisers Good for All Plants?  •  Where and How to Use Liquid Seaweed Fertiliser  •  Using Envii Seaweed Extra  •  When to Use Seaweed Fertiliser?  •  3 Benefits of Seaweed Fertilisers

What is a Seaweed Fertiliser?

Seaweed fertilisers are organic plant feeds containing extracts of seaweed sustainably derived from the ocean. Ascophyllum nodosum is a variety particularly renowned for its ability to boost overall plant health.

Containing beneficial nutrients such as magnesium, potassium, nitrogen and more. Domestically, seaweed fertilisers are most commonly used by gardeners who wish to avoid animal-derived or chemical fertilisers, whilst cultivating the long-term benefits of organic gardening.

Seaweed fertilisers can come in liquid, powdered or granular form.

However, liquid seaweed fertilisers tend to be the most popular. This is because in most cases, liquid fertilisers deliver quicker results in comparison to solid. That’s because solid fertilisers first need to break down and become soluble for plants to take them in, while liquid fertilisers are readily consumable.

Additionally, it can be difficult to track the rate at which plants are taking in solid fertilisers. Which makes it difficult for gardeners to keep up with a regular feeding routine.

Are Seaweed Fertilisers Good for All Plants?

All types of plants can benefit from seaweed fertilisers. Containing complex carbs and vital minerals, seaweed extract delivers every plant with the valuable nutrients needed to grow and thrive.

In fact, seaweed fertilisers have the broadest range of benefits to plants beyond plant nutrition. They also promote bacterial activity in soil mediums. Known to improve root nutrient intake. Along with having the ability to improve resistance to disease, pests and abiotic plant stress.

Key Term: Abiotic Stress – The effect of non-living factors on living organisms within an environment. Examples of abiotic stress in plants include hot/cold weather, soil salinity, drought and heavy metals.

Where and How to Use Liquid Seaweed Fertiliser

Seaweed fertilisers can be used all around your garden. Whether that’s on your lawn, fruit and vegetable patch or on flowers. Of course, your results will vary depending on where you use the treatment.

For example, you will find that your lawn is lush and evenly green in comparison to an untreated lawn. While your fruit and vegetable garden will benefit from greater and healthier harvests.

However, the most important thing to understand is how to use liquid seaweed fertilisers, especially liquid forms, because this will greatly determine the results of the treatment. Liquid seaweed fertilisers are strong; therefore, dilution is essential to avoid burning seeds and roots.

Always check the instructions for dilution rates. Not all plants are the same, so it’s not one size fits all when it comes to feeding them.

Using Envii Seafeed Xtra

When it comes to our own premium quality feed, Seafeed Xtra, here at Envii, we recommend that gardeners only start treating cropping or flowering plants when they have an average of 3 leaves. Treating seedlings when they’re too young can possibly cause damage. Even when diluted, due to over fertilisation.

Young plants will only have one root. However, when a plant is showing 3 leaves this indicates it has established root growth. Allowing them to take on additional nutrients.

You can buy our Seaweed Xtra online, with free UK delivery!

When to Use Seaweed Fertiliser?

Apply these fertilisers when plants are actively growing. I.e. in the midst of the gardening season. In the UK, this is generally between March and September.

However, Seafeed Xtra contains seaweed that has been extracted at a specific time and state. This allows the seaweed to transfer stress resisting nutrients onto other plants. So, those of you who are growing in Autumn and Winter can benefit from treating overwintering plants with a year-round feed.

3 Benefits of Seaweed Fertilisers

We love seaweed fertilisers, and they can really boost your plants. Here are 3 benefits of using seaweed fertilisers.

1. Naturally Occurring Growth Stimulants

Unlike most other fertilisers, they contain naturally occurring growth stimulants for increasing crop yields that often can’t be found elsewhere.

2. Helps Improves Plant Health

They not only increase crop yield, but they also improve plant health through resistance to stress, disease, illness and pests.

3. Longer Lasting Fruit & Veg

Fruits and vegetables grown with seaweed fertilisers benefit from longer life after maturity. Nothing will go to waste and you won’t have to bin any of your bumper crops!

Enjoyed this seaweed fertiliser guide? Learn more about the goodness of seaweed with our guide to the benefits of liquid seaweed.

Related Products

  • Seafeed Xtra 1L Front - Organic Gardening Products

    Envii SeaFeed Xtra

    Organic seaweed fertiliser improves plant growth and health.
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We have a dirty water system that goes to a part of the garden, can you put seaweed extra into the water before it is released onto the garden?

Ingrid Horn

Can seaweed fertiliser be used on acid loving plants