10 Best Organic Liquid Kelp Fertilizer of 2026

Tested and Reviewed: Top 10 Organic Liquid Kelp Fertilizer deals with expert ratings from 8.1 to a perfect 10

June 2026 Edition

Editor's Choice

9.7

GS Plant Foods

GS Plant Foods Liquid Fish & Kelp Fertilizer (1 Quart) – Organic Material Review Institute Listed Natural Plant Food for Home Gardens, and Vegetables

Editor's bottom line:

“This organic liquid kelp fertilizer is the best one we tested. In terms of quality, brand and price, we couldn't ask for more.”

Main Highlights

ORGANIC MATERIALS REVIEW INSTITUTE LISTED FOR TRUSTED GARDEN CARE Certified by OMRI for use in organic growing, GS Plant Foods Liquid Fish & Kelp Fertilizer delivers reliable, natural nutrition for vegetables, flowers, and shrubs.
SEA-AND-SOIL BASED NUTRITION Made from North Atlantic seaweed (Ascophyllum nodosum) and fresh fish hydrolysate, this liquid concentrate delivers natural plant nutrition and beneficial organic compounds that help maintain healthy soil and support productive plants.
SUPPORTS SOIL MICROBIOLOGY & NUTRIENT UPTAKE Supports a thriving soil ecosystem that promotes strong root systems and efficient nutrient absorption the foundation for resilient, productive plants.
EASY-TO-USE CONCENTRATE FOR ALL PLANTS Mix 2 oz per gallon of water and apply as a foliar spray or soil drench every 24 weeks. Safe for use on vegetables, fruits, ornamentals, turf, and houseplants.
MADE IN THE USA SUSTAINABLY PRODUCED Proudly produced by GS Plant Foods, LLC as a fully licensed fertilizer manufacturer (License F003717). No synthetic chemicals, additives, or fillers just natural ingredients formulated for healthy home gardens and hobby farms.

Show Price

Picked by 397 people today

9.5

GS Plant Foods

GS Plant Foods Liquid Fish & Kelp Fertilizer – (1 Gallon) Organic Material Review Institute Listed Natural Plant Food for Home Gardens, Lawns, and Vegetables

Main Highlights

ORGANIC MATERIALS REVIEW INSTITUTE LISTED FOR TRUSTED GARDEN CARE Certified by OMRI for use in organic growing, GS Plant Foods Liquid Fish & Kelp Fertilizer delivers reliable, natural nutrition for vegetables, flowers, and shrubs.
SEA-AND-SOIL BASED NUTRITION Made from North Atlantic seaweed (Ascophyllum nodosum) and fresh fish hydrolysate, this liquid concentrate delivers natural plant nutrition and beneficial organic compounds that help maintain healthy soil and support productive plants.
SUPPORTS SOIL MICROBIOLOGY & NUTRIENT UPTAKE Supports a thriving soil ecosystem that promotes strong root systems and efficient nutrient absorption the foundation for resilient, productive plants.
EASY-TO-USE CONCENTRATE FOR ALL PLANTS Mix 2 oz per gallon of water and apply as a foliar spray or soil drench every 24 weeks. Safe for use on vegetables, fruits, ornamentals, turf, and houseplants.
MADE IN THE USA SUSTAINABLY PRODUCED Proudly produced by GS Plant Foods, LLC as a fully licensed fertilizer manufacturer (License F003717). No synthetic chemicals, additives, or fillers just natural ingredients formulated for healthy home gardens and hobby farms.

Show Price

9.5

GS Plant Foods

GS Plant Foods Liquid Kelp Fertilizer – Suitable for Organic Growing, OMRI Listed Seaweed Concentrate for Lawns, Gardens & Soil - 1 Gallon (Makes Up To 800+ Gallons)

Main Highlights

OMRI Listed & Suitable for Organic Growing GS Plant Foods kelp fertilizer meets the National Organic Program requirements for use in organic production. Ideal for gardeners, farmers, and home growers.
Natural Seaweed Extract from Ascophyllum Nodosum Sourced from one of the most nutrient-rich marine plants, this kelp fertilizer enhances chlorophyll production, root development, and nutrient uptake.
Feeds from the Roots Up Encourages strong root systems and improves overall soil health, leading to stronger, more resilient plants.
Promotes Green, Resilient, Thriving Plants Supports plant vitality under stress conditions like heat, drought, and poor soil quality.
Boosts Flowering & Growth Helps improve plant productivity and bloom quality in vegetables, flowers, lawns, and shrubs.

Show Price

9.2

GS Plant Foods

GS Plant Foods Liquid Kelp Fertilizer – Suitable for Organic Growing, OMRI Listed Seaweed Concentrate for Flowers, Gardens, Vegetables & Soil - 1 Quart (Makes Up to 200+ Gallons)

Main Highlights

OMRI Listed & Suitable for Organic Growing GS Plant Foods kelp fertilizer meets the National Organic Program requirements for use in organic production. Ideal for gardeners, farmers, and home growers.

Show Price

9.0

Bloom City

Bloom City Seaweed and Kelp Fertilizer – Liquid Seaweed Supplement for Stronger Roots, Faster Growth & Improved Stress Tolerance, 32 oz

Main Highlights

Organic Seaweed & Kelp Fertilizer Seaweed fertilizer for plants made from clean kelp seaweed fertilizer sources for natural plant nutrition.
Supports Root Growth & Plant Health Kelp fertilizer helps promote strong roots, improved nutrient uptake, and overall plant resilience.
Supports Root Growth & Plant Health Kelp fertilizer helps promote strong roots, improved nutrient uptake, and overall plant resilience.
Enhances Plant Performance Seaweed kelp formula supports plant strength, growth consistency, and environmental stress tolerance.
Made in USA

Show Price

8.8

Bloom City

Bloom City Seaweed and Kelp Fertilizer – Liquid Seaweed Supplement for Stronger Roots, Faster Growth & Improved Stress Tolerance, 1 Gallon

Main Highlights

Organic Seaweed & Kelp Fertilizer Seaweed fertilizer for plants made from clean kelp seaweed fertilizer sources for natural plant nutrition.
Supports Root Growth & Plant Health Kelp fertilizer helps promote strong roots, improved nutrient uptake, and overall plant resilience.
Supports Root Growth & Plant Health Kelp fertilizer helps promote strong roots, improved nutrient uptake, and overall plant resilience.
Enhances Plant Performance Seaweed kelp formula supports plant strength, growth consistency, and environmental stress tolerance.
Made in USA

Show Price

8.6

Blue Planet Nutrients

Liquid Kelp Seaweed Fertilizer Concentrate - Blue Planet Nutrients Ascophyllum Nodosum Liquid Seaweed Supplement - Makes 470 Gallons - Quart (32 oz)

Main Highlights

Explosive Root & Plant Vitality: Premium liquid kelp concentrate derived from Ascophyllum nodosum seaweed delivers natural growth hormones, trace minerals, and amino acids for stronger roots and lush foliage in every garden.
Makes Up to 470 Gallons from One Quart: Super-concentrated liquid seaweed fertilizer use just ½2 tsp per gallon (2.510 ml) in soil, hydroponic, coco coir, or aeroponic systems and turn one quart into up to 470 gallons of ready-to-use plant food.
Stress & Drought Defense: Seaweed extract boosts natural resistance to heat, cold, transplant shock, and drought while improving nutrient uptake perfect for vegetables, flowers, herbs, fruit trees, and houseplants.
Safe From Seedling to Harvest & Every Application Method: Use as root drench, foliar spray, reservoir additive, or transplant soak 100 % soluble, non-clogging, and gentle enough for clones and seedlings yet powerful through flowering and fruiting.
Trusted by Thousands of Growers: 4.7 Stars from 3,570+ Verified Reviews Made from Organic Ascophyllum Nodosum Seaweed, Vegan, and Proven in Hydro, Soil, and Outdoor Gardens Nationwide.

Show Price

8.3

Bloom City

Bloom City Seaweed and Kelp Fertilizer – Liquid Seaweed Supplement for Stronger Roots, Faster Growth & Improved Stress Tolerance, 8 oz

Main Highlights

Organic Seaweed & Kelp Fertilizer Seaweed fertilizer for plants made from clean kelp seaweed fertilizer sources for natural plant nutrition.
Supports Root Growth & Plant Health Kelp fertilizer helps promote strong roots, improved nutrient uptake, and overall plant resilience.
Supports Root Growth & Plant Health Kelp fertilizer helps promote strong roots, improved nutrient uptake, and overall plant resilience.
Enhances Plant Performance Seaweed kelp formula supports plant strength, growth consistency, and environmental stress tolerance.
Made in USA

Show Price

Best Value

8.1

Save 10%

Neptune's Harvest

Neptune’s Harvest Seaweed Plant Food (0-0-1) - Multi-Purpose Seaweed Organic Liquid Fertilizer - Indoor & Outdoor Plant Fertilizer for Lawns, Gardens, Vegetables, & Flowers (Pint)

10% Off

Main Highlights

Derived for Maximum Growth: Neptunes Harvest Organic Seaweed Plant Food is an organic seaweed liquid fertilizer made from Ascophyllum Nodosum seaweed (Norwegian kelp) in liquid form, harvested from cold North Atlantic waters; this liquid fertilizer acts as a natural storehouse of over 60 nutrients, amino acids, trace minerals, and natural growth promoters, making it suitable for both indoor & outdoor plants including houseplants, vegetables, flowers, and lawns and is safe for kids and pets
Power of Seaweed Nutrients: This organic seaweed plant food provides naturally occurring nutrients and amino acids that support plant hardiness, stress recovery, and overall plant performance; formulated as a 0-0-1 seaweed liquid fertilizer, it supplies potassium while remaining OMRI Listed, making this organic seaweed liquid fertilizer a dependable choice for routine plant feeding
How to Use: This versatile seaweed liquid fertilizer is easy to use for both indoor and outdoor plants; for houseplants, mix 1 tablespoon per gallon of water and feed weekly; for outdoor plants like vegetables, flowers, and shrubs, mix 1/8 cup (1 fl oz.) per gallon of water and apply every 1-2 weeks; you can also use it as a foliar feed for plant foliage or apply it to lawns to cover up to 8,000 sq. ft. during the growing season
Supports Plant Recovery: This organic seaweed plant food works as a reliable rescue product when plants experience stress, helping increase plant hardiness and offering frost protection; this fertilizer sequesters carbon, builds organic matter, and helps soil drain yet retain moisture; when used as a foliar feed, this liquid plant fertilizer can help address powdery mildew and support longer shelf-life on produce, making it a practical organic seaweed solution
Package Contents: Neptunes Harvest Seaweed Plant Food (0-0-1)

Show Price

8.1

Smart Grower

Organic Sea Kelp Fertilizer for Plants – Water-Soluble – Makes 50 Gallons – Kelp Meal Concentrate Plant Food – for Indoor Gardens, Hydroponics, Vegetables, Houseplants - Smart Grower - 2oz Bag

Main Highlights

Organic Bio-Active Seaweed Harvested From Maine, USA - Smart Grower Sea-Kelp (Ascophyllum Nodosum) is boosted with rich source of naturally-derived organic polymers (fucoidan, alginate, and tannins) for maximum plant growth with NPK: 0-0-18 Soluble potash for enhanced nutrient uptake in plants
6X Stronger Super-Concentrated Powder - 2 oz pouch makes up to 50 gallons of highly water soluble powder mixable liquid kelp fertilizer for large and small indoor gardens, vegetable beds, and hydroponics and houseplants this is the best value on the market
Healthier Bigger Plants Fast - Our Cold-Water Harvested in Maine Sea-Kelp plant food will boost your garden health and plant root strength because this organic kelp fertilizer supports natural plant stress resistance and maximum nutrient efficiency in all plant growing systems.
Fast Results Proven and Trusted Organic Fertilizer - Thousands of farmers and gardeners use Smart Grower Sea-Kelp Meal Fertilizer to boost plant health for houseplants, vegetables, flowers, and hydroponic systems including seedlings and mature crops to get larger yields and bigger plants
Easy-to-Use, and Compatible with Nutrients - Smart Grower Sea-Kelp fertilizer is fast-dissolving and easy to mix with water, simply apply every 1 to 2 weeks for stronger plants and bigger yields for all types of plants, gardens, and growing mediums
Cruelty-Free, Organic, Small Batch, Non-GMO, Responsibly Harvested Sea-Kelp Plant Food All Smart Grower products are made in small batches to help restore the poisoned ecosystem of this planet for the optimal health of people, plants, and our planet

Show Price

Our Best Overall Choice

Best Choice

9.7

GS Plant Foods

GS Plant Foods Liquid Fish & Kelp Fertilizer (1 Quart) – Organic Material Review Institute Listed Natural Plant Food for Home Gardens, and Vegetables

Editor's bottom line:

“This is the best one we tested. In terms of quality, brand and price, we couldn't ask for more.”

Main Highlights

ORGANIC MATERIALS REVIEW INSTITUTE LISTED FOR TRUSTED GARDEN CARE Certified by OMRI for use in organic growing, GS Plant Foods Liquid Fish & Kelp Fertilizer delivers reliable, natural nutrition for vegetables, flowers, and shrubs.
SEA-AND-SOIL BASED NUTRITION Made from North Atlantic seaweed (Ascophyllum nodosum) and fresh fish hydrolysate, this liquid concentrate delivers natural plant nutrition and beneficial organic compounds that help maintain healthy soil and support productive plants.
SUPPORTS SOIL MICROBIOLOGY & NUTRIENT UPTAKE Supports a thriving soil ecosystem that promotes strong root systems and efficient nutrient absorption the foundation for resilient, productive plants.
EASY-TO-USE CONCENTRATE FOR ALL PLANTS Mix 2 oz per gallon of water and apply as a foliar spray or soil drench every 24 weeks. Safe for use on vegetables, fruits, ornamentals, turf, and houseplants.
MADE IN THE USA SUSTAINABLY PRODUCED Proudly produced by GS Plant Foods, LLC as a fully licensed fertilizer manufacturer (License F003717). No synthetic chemicals, additives, or fillers just natural ingredients formulated for healthy home gardens and hobby farms.

Show Price

Deals are Live

Special Amazon deal ends in: