10 Best Seaweed Liquid Fertilizer in The UK

Last updated on 29/06/2025

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Multi-Mite® 20 Ltr LIQUID SEAWEED - ORGANIC Concentrate Plant Fertiliser Tomato, Trees Lawn Veg and House Plants Root or Foliar Feed

Why We Love It

100% Natural and Organic.
Promotes soil and plant health.
Suitable for all plants.

Main Highlights

✅ MULTI-MITE ORGANIC LIQUID SEAWEED CONCENTRATE - Is 100% Natural and Organic Plant Feed and Plant and Soil Conditioner - COLD PRESSED. Suitable for use on lawns, gardens, sports greens and agricultural land and used all over in Football League Club grounds. Liquid Seaweed helps Promote Stress Resistance, Healthy Sytems from Roots to the leaves. It also Greatly helps to increase soil fertility. Our Seaweed is made from Ascophyllum Nodosum, SUSTAINABLE concentrated from the West Coast of Ireland.
✅ WITH MULTI-MITE SEAWEED SUITABLE FOR ALL PLANTS - Perftect for TOMATO'S, you'll unlock the Power of the Sea for your plants! This Dynamite Fertiliser is filled with beneficial nutrients for your beloved botanicals. Whether you're growing yummy veggies, encouraging a tree to grow, trying to get your lawn to look its best, or just want a little boost for your house plants, this MULTI MITE fertiliser is a great choice.
✅ ELIXIR OF LIFE FOR ALL PLANTS IN A BOTTLE - Our Liquid Seaweed is packed full of Carbohydrates, not only do your plants use complex carbs in their structure and as food, it's also a tasty snack for a host of beneficial Microorganisms that help create the perfect ecosystem for your greenery. Supposedly MULTI MITE Liquid Seaweed Concentrate is so powerful that it may even bring plants previously thought dead back to life!
✅ USED BY PROFESSIONALS AND BY US MORTALS - Ideal for every gardener with greenhearts as well as green fingers, MULTI MITE is completely 100% Natural. ZERO thickeners, colourants or other chemical additives in MULTI MITE plant fertiliser, just PURE Seaweed Extract! It's organic nature is one advantage; another is replaceability, seaweed is a Fully Fresh Bed resource. Kiss artificial Chemical Fertilisers and animal-based goodbye and embrace the oceanic goodness of MULTI MITE Seaweed Concentrate!
✅ BEST USE OF MULTI-MITE LIQUID SEAWEED - This Elixir is suitable for feeding to all manner of plants, trees & grasses, works in hydroponics. Ideally apply concentrate twice weekly. Application rates differ depending on the soil type and plants. It's recommended that you begin with a dilution rate of 10ml per litre for young or sick plants, increase the concentration if no results are visible after one week. Spray leaves directly for Folia usage, the plant intake is up to 20 times root feeding!

Multi-Mite 10 Ltr Liquid Seaweed – 100% Natural & Organic Concentrate Cold Pressed Plant Feed & Soil Fertiliser, Trees Lawn Veg & House Plants Root or Foliar Feeding

Why We Love It

100% natural and organic.
Boosts plants' stress resistance.
Packed with beneficial nutrients.

Main Highlights

✅ MULTI-MITE 10 LITRE ORGANIC LIQUID SEAWEED CONCENTRATE - Is 100% Natural and Organic Plant Feed and Plant and Soil Conditioner - COLD PRESSED. Suitable for use on lawns, gardens, sports greens and agricultural land and used all over in Football League Club grounds. Liquid Seaweed helps Promote Stress Resistance, Healthy Sytems from Roots to the leaves. It also Greatly helps to increase soil fertility. Our Seaweed is made from Ascophyllum Nodosum, concentrated from the West Coast of Ireland.
✅ WITH MULTI-MITE SEAWEED SUITABLE FOR ALL PLANTS - you'll unlock the Power of the Sea for your plants! This Dynamite Fertiliser is filled with beneficial nutrients for your beloved botanicals. Whether you're growing yummy veggies, encouraging a tree to grow, trying to get your lawn to look its best, or just want a little boost for your house plants, this MULTI MITE fertiliser is a great choice.
✅ ELIXIR OF LIFE FOR ALL PLANTS IN A BOTTLE - Our Liquid Seaweed is packed full of Carbohydrates, not only do your plants use complex carbs in their structure and as food, it's also a tasty snack for a host of beneficial Microorganisms that help create the perfect ecosystem for your greenery. Supposedly MULTI MITE Liquid Seaweed Concentrate is so powerful that it may even bring plants previously thought dead back to life!
✅ USED BY PROFESSIONALS AND BY US MORTALS - Ideal for every gardener with greenhearts as well as green fingers, MULTI MITE is completely 100% Natural. ZERO thickeners, colourants or other chemical additives in MULTI MITE plant fertiliser, just PURE Seaweed Extract! It's organic nature is one advantage; another is replaceability, seaweed is a Fully Fresh Bed resource. Kiss artificial Chemical Fertilisers and animal-based goodbye and embrace the oceanic goodness of MULTI MITE Seaweed Concentrate!
✅ BEST USE OF MULTI-MITE LIQUID SEAWEED - This elixir is suitable for feeding to all manner of plants, trees & grasses, works in hydroponics. Ideally apply concentrate twice weekly. Application rates differ depending on the soil type and plants. It's recommended that you begin with a dilution rate of 10ml per litre for young or sick plants, increase the concentration if no results are visible after one week. Spray leaves directly for Folia usage, the plant intake is up to 20 times root feeding!

ALGA-SOL Cold Press Concentrate Seaweed Extract Ascophyllum Seaweed Extract 5Ltr Biostimulant Fertiliser Fertilizer Seaweed Plant Feed Organic Fertiliser Fertilizer

Why We Love It

Balanced pH for all applications.
Loved by professional sportsgrounds.
Preserves natural bioactives effectively.

Main Highlights

Balanced pH: ALGA-SOL Seaweed Extract contains a balanced pH of around 5-6, making it ideal for all applications. Many seaweeds on the market are high in pH due to their chemical extraction. The dangers of using an alkaline based seaweed extract include the onset of diseases such as scab in potatoes.
Developed and used by Professionals: ALGA-SOL Seaweed extract was developed by a team of leading scientists after a 6 year study on seaweed extracts and their extraction methods. Over the years we have gained a large following by several industries and we currently supply a number of companies who manage some of the leading sportsgrounds Globally. In the UK our extract is used every season on Gleneagles Golf Course as well as 60% of the UK Premier League Football Grounds.
Store in a cool & dry place out of direct sunlight.
Seaweed Extract is manufactured via cold-press extraction methods. After hand harvesting the Ascophyllum seaweed is transported and processed via our extraction plant within 6 hours of leaving the sea. This ensures that all natural bioactives are extracted and preserved before they degrade. The cold-press process involves the seaweed being passed through a concentrated point of pressure similar to the extraction of virgin olive oil.
Due to our low temperature extraction process, ALGA-SOL is high in naturally chelated micronutrients, natural anti-oxidants, functional polysaccharides (alginates) as well as bioactives including cytokinins, auxins, mannitol and gibberellins. All of these compounds are found naturally in Ascophyllum nodosum and retain their maximum levels in our unique Cell Harvest Technology process.

Multi-Mite 5 Ltr Liquid Seaweed -100% Natural & Organic Concentrate Cold Pressed Plant & Soil Fertiliser, Trees Lawn Veg & House Plants Root or Foliar Feeding

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Why We Love It

Promotes healthy, stress-resistant plants.
Increases soil fertility naturally.
Revives dying plants effectively.

Main Highlights

✅ MULTI-MITE ORGANIC LIQUID SEAWEED CONCENTRATE - Is 100% Natural and Organic Plant Feed and Plant and Soil Conditioner - COLD PRESSED. Suitable for use on lawns, gardens, sports greens and agricultural land and used all over in Football League Club grounds. Liquid Seaweed helps Promote Stress Resistance, Healthy Sytems from Roots to the leaves. It also Greatly helps to increase soil fertility. Our Seaweed is made from Ascophyllum Nodosum, concentrated from the West Coast of Ireland.
✅ WITH MULTI-MITE SEAWEED SUITABLE FOR ALL PLANTS - you'll unlock the Power of the Sea for your plants! This Dynamite Fertiliser is filled with beneficial nutrients for your beloved botanicals. Whether you're growing yummy veggies, encouraging a tree to grow, trying to get your lawn to look its best, or just want a little boost for your house plants, this MULTI MITE fertiliser is a great choice.
✅ ELIXIR OF LIFE FOR ALL PLANTS IN A BOTTLE - Our Liquid Seaweed is packed full of Carbohydrates, not only do your plants use complex carbs in their structure and as food, it's also a tasty snack for a host of beneficial Microorganisms that help create the perfect ecosystem for your greenery. Supposedly MULTI MITE Liquid Seaweed Concentrate is so powerful that it may even bring plants previously thought dead back to life!
✅ USED BY PROFESSIONALS AND BY US MORTALS - Ideal for every gardener with greenhearts as well as green fingers, MULTI MITE is completely 100% Natural. ZERO thickeners, colourants or other chemical additives in MULTI MITE plant fertiliser, just PURE Seaweed Extract! It's organic nature is one advantage; another is replaceability, seaweed is a Fully Fresh Bed resource. Kiss artificial Chemical Fertilisers and animal-based goodbye and embrace the oceanic goodness of MULTI MITE Seaweed Concentrate!
✅ BEST USE OF MULTI-MITE LIQUID SEAWEED - This Elixiar is suitable for feeding to all manner of plants, trees & grasses, works in hydroponics. Ideally apply concentrate twice weekly. Application rates differ depending on the soil type and plants. It's recommended that you begin with a dilution rate of 10ml per litre for young or sick plants, increase the concentration if no results are visible after one week. Spray leaves directly for Folia usage, the plant intake is up to 20 times root feeding!

Multi-Mite 2.5L Liquid Seaweed Organic Cold Pressed Concentrate - 100% Natural - Plant Feed Fertiliser Trees Lawn Veg & House Plants Root or Foliar Feed (2.5 LITRES)

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Why We Love It

Promotes healthy, stress-resilient plants.
Boosts soil fertility effectively.
Suitable for various plants.

Main Highlights

MULTI-MITE ORGANIC LIQUID SEAWEED CONCENTRATE - Is 100% Natural and Organic Plant Feed and Plant and Soil Conditioner - COLD PRESSED. Suitable for use on lawns, gardens, sports greens and agricultural land and used all over in Football League Club grounds. Liquid Seaweed helps Promote Stress Resistance, Healthy Sytems from Roots to the leaves. It also Greatly helps to increase soil fertility. Our Seaweed is made from Ascophyllum Nodosum, concentrated from the West Coast of Ireland.
WITH MULTI-MITE SEAWEED SUITABLE FOR ALL PLANTS - you'll unlock the Power of the Sea for your plants! This Dynamite Fertiliser is filled with beneficial nutrients for your beloved botanicals. Whether you're growing yummy veggies, encouraging a tree to grow, trying to get your lawn to look its best, or just want a little boost for your house plants, this MULTI MITE fertiliser is a great choice
ELIXIR OF LIFE FOR ALL PLANTS IN A BOTTLE - Our Liquid Seaweed is packed full of Carbohydrates, not only do your plants use complex carbs in their structure and as food, it's also a tasty snack for a host of beneficial Microorganisms that help create the perfect ecosystem for your greenery. Supposedly MULTI MITE Liquid Seaweed Concentrate is so powerful that it may even bring plants previously thought dead back to life!
USED BY PROFESSIONALS AND BY US MORTALS - Ideal for every gardener with greenhearts as well as green fingers, MULTI MITE is completely 100% Natural. ZERO thickeners, colourants or other chemical additives in MULTI MITE plant fertiliser, just PURE Seaweed Extract! It's organic nature is one advantage; another is replaceability, seaweed is a Fully Fresh Bed resource. Kiss artificial Chemical Fertilisers and animal-based goodbye and embrace the oceanic goodness of MULTI MITE Seaweed Concentrate!
BEST USE OF MULTI-MITE LIQUID SEAWEED - This Elixir is suitable for feeding to all manner of plants, trees & grasses, works in hydroponics. Ideally apply concentrate twice weekly. Application rates differ depending on the soil type and plants. It's recommended that you begin with a dilution rate of 10ml per litre for young or sick plants, increase the concentration if no results are visible after one week. Spray leaves directly for Folia usage, the plant intake is up to 20 times root feeding!

6 x Doff 1L Liquid Seaweed Concentrated Multi-Purpose Feed

Why We Love It

Highly concentrated and effective.
Promotes plant growth naturally.
Easy to use formula.

Main Highlights

6 x Doff 1L Liquid Seaweed Concentrated Multi-Purpose Feed
Product type: FERTILIZER
Brand: Doff Portland Ltd

Pro-Kleen Organic Liquid Seaweed Fertiliser 5L - Ascophyllum Seaweed Extract for Grass, Vegetables, Fruit, Flowers, Shrubs, Lawns & Trees - Concentrated Formula - Provides up to 500 Treatments

Why We Love It

Organic and natural ingredients.
Promotes robust plant growth.
Suitable for various plants.

Main Highlights

ORGANIC SEAWEED FERTILISER: Experience the power of Pro-Kleen's Liquid Seaweed Fertilizer, offering a comprehensive blend of essential nutrients to support your plants, vegetables, fruit, grass & more. Our specialized formula is designed to stimulate rapid and robust growth, ensuring that your crops thrive
CONTAINS 100% NATURAL & ORGANIC SEAWEED: Unlike other fertilisers, Pro-Kleen's formula contains natural and organic seaweed. Seaweed boasts exceptional properties that promote plant health by improving stress tolerance, nutrient absorption, growth, root development, flowering, and even reducing seed dormancy. Derived from seaweed, Pro-Kleen's fertilizers contain polysaccharides, proteins, and fatty acids, all of which contribute to better moisture and nutrient retention, resulting in stronger, healthier plant growth!
SUITABLE FOR A VARIETY OF PLANTS: This garden fertilizer is suitable for use on grass, soil, fruit, vegetables, flowers, shrubs, lawns & trees
ENRICHED FORMULA: Our enhanced formula includes amino acids, trace elements, trace minerals, and iron, providing your grass, vegetation, flowers, and more with everything they need for optimal growth. Amino acids play a crucial role in regulating root and flower development while stimulating overall growth. Trace elements and minerals promote robust growth and contribute to the overall health and strength of plants. Iron facilitates the vital transportation of oxygen within the plant, aiding its distribution through roots, leaves, and other plant parts. Together, these elements yield exceptional results, ensuring the flourishing of your plants!
CONCENTRATED FORMULA: Just one 5-litre bottle can provide up to 500 treatments! It’s a super easy-to-use formula to make sure your plants look and grow better than ever.

Elixir Gardens | Organic Hebridean Liquid Seaweed Fertiliser | 500ml - 20L Options Available | 5 Litre Bottle

Why We Love It

100% natural and organic.
Promotes healthy, stress-resistant plants.
Increases soil fertility effectively.

Main Highlights

Seaweed Meal - Elixir Gardens seaweed meal is a 100% natural and organic plant feed and conditioner, certified by the Soil Association. It is suitable for use on lawns, gardens, sports greens and agricultural land. Seaweed meal helps promote stress resistant, healthy sward. It also helps to increase soil fertility. This seaweed meal is made from Ascophyllum Nodosum, concentrated from the Northern Atlantic. Application Rate - Top dressing: 35g - 75g per square metre.
Liquid Seaweed - Our liquid seaweed stimulates healthy plants, producing higher yields of crops and more flowers. Harvested sustainably from the isles of the Outer Hebrides, this nutrient rich Atlantic seaweed is completely free from any additives and chemicals. Application Rate-As a general guide we recommend a dilution rate of 50ml of liquid seaweed per litre of water. Dosage will depend on the type of plant or crop being treated however.
Liquid Seaweed + Iron - Liquid seaweed with added iron will help make your lawn a beautiful dark green colour. Additionally, Liquid seaweed will harden sward reducing the soil-s susceptibility to disease and cold damage. The iron present in the liquid will also discourage moss formation and worm activity.
Calcified Seaweed - Elixir calcified seaweed is 100% natural, made from naturally occurring beds of calcified and coralline algae. Calcified seaweed serves to increase soil pH over time, as well as improving soil structure. It contains trace elements and plant nutrients making it useful as a spring lawn dressing. Application Rate: 100g per square metre.
NOTE: The appearance of this fertiliser can change between batches due to the raw ingredients used in production. Additionally supplied packaging may differ from that displayed.

2 X Doff 1L Liquid Seaweed Concentrated Multi-Purpose Feed

10% Off

Why We Love It

Promotes healthier plant growth.
Suitable for all plants.
Highly concentrated formula.

Main Highlights

2 X Doff 1L Liquid Seaweed Concentrated Multi Purpose Feed
Brand : Doff
Product Type : Fertilizer

envii SeaFeed Xtra – Organic Seaweed Fertiliser, Liquid Outdoor Plant Food Ideal for all Plants, Lawns, Gardens and House Plants, Rich in Additional Nutrients - 1 Litre Makes up to 500L

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Why We Love It

Promotes strong plant growth.
Multi-purpose with added extras.
Easy application process.

Main Highlights

Boosts Plant Growth & Crop Yields - Natural Seaweed fertiliser that enhances strong & healthy plant growth, promotes lush foliage, and increases crop yields for thriving plants.
Nutrient Rich Plant Food - Enriched with iron and plant-based amino acids to nourish garden plants, improve soil health, and support plant & root development.
Versatile & All Purpose - Ideal for lawns, fruits, vegetables, flowers, trees, and all other garden plants. Perfect for any outdoor or indoor plants.
100% Organic & Vegan - Seafeed Xtra is made from natural, sustainably sourced ingredients & certified Organic by OF&G.
User Friendly Design: Comes with an easy-to-use bottle featuring a built-in measuring chamber for hassle-free application. One litre of Seafeed Xtra makes up to 500 litres of feed when diluted, suited for all size gardens.

8.7

Excellent

We scanned 269 products

We reviewed these offers relevant to the Seaweed Liquid Fertilizer within online retailers such as Amazon, eBay and other local retailers, ensuring we covered all major brands and models. The products we selected come from trusted brands like Multi-Mite, Mifica, Doff Portland Ltd, Pro-Kleen, Elixir Gardens, Doff, envii, all of which have a reputation for consistently delivering high-quality products that users love and innovative approaches for function & design.

For the best Seaweed Liquid Fertilizer in the market, we considered we took a deep dive into 1346 online reviews , focusing on elements like user satisfaction, performance in real-world conditions, and long-term reliability. Our ranking also evaluates each review’s relevancy, authenticity, up-to-dateness and depth so that the comparison is more sound.

We concluded that:

The clear winner of our analysis is Multi-Mite® 20 Ltr LIQUID SEAWEED - ORGANIC Concentrate Plant Fertiliser Tomato, Trees Lawn Veg and House Plants Root or Foliar Feed. We love many things about this product by Multi-Mite. What sets it apart from the competition is 100% Natural and Organic, Promotes soil and plant health, Suitable for all plants.
The best value product for most shoppers and where user satisfaction is continuously the highest is Multi-Mite 10 Ltr Liquid Seaweed – 100% Natural & Organic Concentrate Cold Pressed Plant Feed & Soil Fertiliser, Trees Lawn Veg & House Plants Root or Foliar Feeding by Multi-Mite based on online reviews by bloggers, experts and online shoppers.
The biggest bargain at the moment for Seaweed Liquid Fertilizer and the best cost-to-value ratio is 2 X Doff 1L Liquid Seaweed Concentrated Multi-Purpose Feedat Doff with a 10% discount.
Our list of the best Seaweed Liquid Fertilizer is updated regularly to reflect new releases and changes in product availability, so be sure to check back often for the latest rankings and discounts.

10 Best Seaweed Liquid Fertilizer in The UK

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We scanned 269 products

We concluded that: