Comparison: Best Kelp Emulsion Fertilizer (Updated | Dec 1st)
If your garden’s been craving a natural boost, you’ve probably heard about kelp emulsion fertilizers—but with so many options out there, how do you know which one’s truly the best? We’ve dug into the details, tested top brands, and compared ingredients, value, and real results to help you choose wisely.
- Best for omri certified: GS Plant Foods Liquid Fish & Kelp Fertilizer (1 Gallon) – Organic Material Review Institute Listed Natural Plant Food for Home Gardens
- Best for fast-acting boost: Down To Earth All Natural Fertilizers Organic Liquid Fish & Kelp Concentrate – Plant Food for Vegetable Gardens and Flower Beds – Makes up to 32 Gallons 2-4-1
- Best for seven-species blend: Bloom City Organic Liquid Seaweed and Kelp Fertilizer Supplement
- Best for whole-fish power: Organic Fish Emulsion with Kelp
- Best for compact emulsion: EB Stone Fish Emulsion with Kelp
- Best for pure kelp extract: GS Plant Foods Liquid Kelp Fertilizer – Suitable for Organic Growing
- Best for 50-gallon power: Organic Sea Kelp Fertilizer for Plants – Water-Soluble – Makes 50 Gallons – Kelp Meal Concentrate Plant Food – for Indoor Gardens
- Best for wintergreen fresh: Alaska Fish Emulsion Fertilizer 5-1-1 Concentrate 1 Gallon (Packaging may vary)
- Best for bulk clean kelp: Bloom City Organic Liquid Seaweed and Kelp Fertilizer Supplement (128 oz) Concentrated Makes 750 Gallons
- Best for yield-boost emulsion: 1 Gallon Organic Fish Emulsion Fertilizer for Plants – Ideal Liquid Fish Fertilizer for Plants
Product Comparison: Best Kelp Emulsion Fertilizer
GS Plant Foods Liquid Fish & Kelp Fertilizer (1 Gallon) – Organic Material Review Institute Listed Natural Plant Food for Home Gardens, Lawns, and Vegetables
- 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, lawns, flowers, and shrubs.
- SEA-AND-SOIL BASED NUTRITION Made from North Atlantic seaweed (Ascophyllum nodosum) and fresh fish hydrolysate, this liquid concentrate provides essential nutrients and trace minerals that help support healthy soil and plant development.
- IMPROVES 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 2–4 weeks. Safe for use on vegetables, fruits, ornamentals, turf, and houseplants.
- MADE IN THE USA – SUSTAINABLY PRODUCED Proudly produced by GS Plant Foods as a licensed fertilizer manufacturer. No synthetic chemicals, additives, or fillers — just natural ingredients formulated for healthy home gardens and hobby farms.
Down To Earth All Natural Fertilizers Organic Liquid Fish & Kelp Concentrate – Plant Food for Vegetable Gardens and Flower Beds – Makes up to 32 Gallons 2-4-1, 32 oz
- Fast‑acting liquid formula: Perfect for foliar feed or soil drench applications, supporting quick absorption and growth stimulation.
- Stimulates overall plant vigor: High phosphorus aids flowering and fruiting, while nitrogen supports lush foliage and root development.
- Organic & soil‑friendly: Helps promote beneficial microbial activity and sustainable soil health due to its fish and kelp base
- Versatile application rates: For general garden use: ¼–½ cup per gallon of water; for containers: 2–4 Tbsp per gallon; for houseplants: 2 Tbsp per gallon, repeated every 2–4 weeks depending on growth stage
- Watch out for odor: While extremely effective, many users report a strong fish-like odor characteristic of fish emulsions—though it typically subsides quickly and doesn’t linger long indoors
Bloom City Organic Liquid Seaweed and Kelp Fertilizer Supplement, Quart (32 oz) Concentrated Makes 180 Gallons
- FULLY ORGANIC SEAWEED AND KELP: A seven species blend of Ascophyllum Nodosum, Palmaria Palmata, Ecklonia Maxima, Laminaria Saccharina, Chlorella Vulgaris, Arthrospira Platensis, and Chondrus Crispus.
- EXTRACTED TO PROTECT NATURAL ENZYMES: Clean Kelp’s unique processing techniques give the cleanest possible kelp extract. Get all the benefits of natural kelp enzymes and hormones without the non-nutritious fibrous pulp that gives other kelps their thick, brackish appearance. You can see the difference.
- SIMPLE AND SAFE TO USE FOR ALL PLANTS: Add to every watering, it’s that easy. No risk of over application, plants love kelp. Clean Kelp aids in every stage of growth for root and stem health.
- FOR BOTH PLANTS AND LAWNS: Add Clean Kelp to all of your houseplants, vegetable garden, and your lawn for healthy green plants.
- FORMULATED AND MADE IN THE USA: Designed by botanists and plant chemists. Bloom City chooses only the highest quality ingredient sources and manufacturing methods to create the world’s best craft growing nutrient systems
Organic Fish Emulsion with Kelp, one Gallon Size
- All natural plant food to help plants grow, flower, fruit and stay deep green.
- This liquid fertilizer is concentrated and must be diluted before use.
- Derived from: Whole fish and Kelp.
- One Gallon Size
EB Stone Fish Emulsion with Kelp, Quart Size
- All natural plant food to help plants grow, flower, fruit and stay deep green.
- This liquid fertilizer is concentrated and must be diluted before use.
- Derived from: Whole fish and Kelp.
- Quart size
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)
- Organic Materials Review Institute Listed for Organic Use- Certified for use in organic gardening and farming, this natural seaweed extract fertilizer made from Ascophyllum Nodosum provides a balanced source of trace minerals and organic compounds that nourish plants and soil.
- Supports Soil Health & Nutrient Availability- Helps maintain favorable soil conditions and assists in nutrient uptake from the soil, contributing to healthy, productive plants.
- Suitable for All Types of Plants- Safe and effective for vegetables, fruits, ornamentals, lawns, trees, and shrubs—used by home gardeners and commercial growers as part of a regular fertility program.
- Simple, Flexible Application- Mix 2 ounces of concentrate per gallon of water and apply to soil or foliage with a sprayer, watering can, or hose-end sprayer. One gallon of solution treats up to 1,000 sq. ft.
- Trusted Quality from GS Plant Foods- We take pride in producing sustainable, high-quality organic fertilizers that are easy to use and compatible with any growing system. Consistent performance backed by a satisfaction commitment.
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
- 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
Alaska Fish Emulsion Fertilizer 5-1-1 Concentrate 1 Gallon (Packaging may vary)
- Will Not Burn
- Great for all plants
- Deodorized with Natural Wintergreen
- 5-1-1 fertilizer is an excellent source of organic plant nutrients
- Fish Fertilizer
Bloom City Organic Liquid Seaweed and Kelp Fertilizer Supplement (128 oz) Concentrated Makes 750 Gallons
- FULLY ORGANIC SEAWEED AND KELP: A seven species blend of Ascophyllum Nodosum, Palmaria Palmata, Ecklonia Maxima, Laminaria Saccharina, Chlorella Vulgaris, Arthrospira Platensis, and Chondrus Crispus.
- EXTRACTED TO PROTECT NATURAL ENZYMES: Clean Kelp’s unique processing techniques give the cleanest possible kelp extract. Get all the benefits of natural kelp enzymes and hormones without the non-nutritious fibrous pulp that gives other kelps their thick, brackish appearance. You can see the difference.
- SIMPLE AND SAFE TO USE FOR ALL PLANTS: Add to every watering, it’s that easy. No risk of over application, plants love kelp. Clean Kelp aids in every stage of growth for root and stem health.
- FOR BOTH PLANTS AND LAWNS: Add Clean Kelp to all of your houseplants, vegetable garden, and your lawn for healthy green plants.
- FORMULATED AND MADE IN THE USA: Designed by botanists and plant chemists. Bloom City chooses only the highest quality ingredient sources and manufacturing methods to create the world’s best craft growing nutrient systems
1 Gallon Organic Fish Emulsion Fertilizer for Plants – Ideal Liquid Fish Fertilizer for Plants, Flowers, Fruits & Vegetables, 2-3-1 NPK – Sustainably Sourced and Hydrolyzed for Steady Growth
- ORGANIC FISH EMULSION FERTILIZER – Our liquid fish fertilizer is made from sustainably sourced fish emulsion and we use up all the parts that would otherwise go to waste. Using an environmentally conscious method, ingredients are refined fresh and 100% cold pressed to help retain all of the nutrients, vitamins, and amino acids needed to grow healthy plants.
- GROW PLANTS NATURALLY – This wonderfully organic alternative to synthetic fertilizer contains a 2-3-1 NPK ratio perfect for light and frequent applications. Promotes steady, healthy plant development throughout the growing season.
- ENRICHES SOIL – Helps build a strong foundation for your organic garden to thrive on! Use as an effective soil drench to improve fertility, structure, and encourage the growth of beneficial microorganisms like fungi in your garden’s soil.
- PRODUCE MORE – Get the most out of your fertilizer and your garden! This organic garden fertilizer helps to increase crop yields and flower blooms. Gentle enough to use as a foliar spray makes this the perfect fish fertilizer for plants, flowers, and vegetables.
- SMELL THE DIFFERENCE – This fertilizer smells like fish because it’s made from fish! Crafted with high-quality concentrated and undiluted hydrolyzed fish emulsion each bottle gives off a pungent fishy aroma. When compared, we see it like this – if it doesn’t smell, then it’s not real fish!
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Buying Guide
FAQs
What key factors should I look at when choosing a liquid kelp or fish‑kelp fertilizer?
Check the source of the kelp (e.g., Ascophyllum nodosum from Maine or Atlantic seaweed) and whether the formula includes fish hydrolysate for added nitrogen. Look for certifications like OMRI that confirm organic compliance, and compare concentration ratios to see how much product you need to dilute for each application. Finally, consider the intended use—foliar spray, soil drench, or both—and any added benefits such as microbial support or trace minerals.
How do GS Plant Foods Liquid Fish & Kelp (1 gal) and Down To Earth All Natural Fertilizer differ in nutrient profile and application?
GS Plant Foods blends North Atlantic kelp with fresh fish hydrolysate and is OMRI‑listed, offering a balanced mix of macro‑nutrients and trace minerals for a wide range of plants. Down To Earth emphasizes a higher phosphorus level for flowering and uses a ¼–½ cup per gallon dilution, but many users note a stronger fish odor. Both are applied every 2–4 weeks, yet the GS product’s lower odor and organic certification may make it more appealing for sensitive garden environments.
Which product gives the best value for a large garden or lawn?
The Smart Grower Sea‑Kelp powder (0.5 oz pouch) makes up to 50 gallons of fertilizer, delivering a cost‑effective 6X super‑concentrated solution for extensive beds or lawns. In contrast, the 1‑gallon liquid concentrates from GS Plant Foods or Alaska Fish Emulsion cover roughly 1,000 sq ft per batch, requiring more frequent purchases for large areas. For sheer volume and price per treated square foot, the powder‑based kelp fertilizer offers the strongest value.
Are there odor concerns with fish‑kelp emulsions, and which brands minimize the smell?
Fish‑based emulsions naturally have a fishy scent, which can linger in indoor spaces; Down To Earth and Alaska Fish Emulsion explicitly mention a strong odor. GS Plant Foods’ kelp‑only concentrate (GS Plant Foods Liquid Kelp Fertilizer) contains no fish and therefore eliminates the smell, making it a better choice for indoor or patio use. Some products, like the Alaska Fish Emulsion, are deodorized with natural wintergreen to reduce the odor.
How does a kelp‑only fertilizer compare to a fish‑kelp blend for improving soil health?
Kelp‑only formulas, such as GS Plant Foods Liquid Kelp Fertilizer, provide a rich source of trace minerals, hormones, and organic polymers that enhance nutrient uptake and support beneficial microbes without adding nitrogen. Fish‑kelp blends add extra nitrogen and amino acids, which can boost foliage growth but may also increase the risk of over‑fertilizing if not diluted correctly. For gardeners focused on soil biology and long‑term health, a pure kelp product is often preferred.
What are the advantages of the powder‑based kelp fertilizer (Smart Grower) over liquid concentrates?
The powder form is ultra‑concentrated, allowing a small pouch to create up to 50 gallons of solution, which reduces shipping weight and storage space. It dissolves quickly in water and can be mixed with other nutrient regimens, making it versatile for hydroponics, indoor gardens, and large fields. Liquid concentrates are ready‑to‑mix but require more frequent repurchasing and can be heavier to transport.
Which kelp or fish‑kelp fertilizer is most suitable for indoor houseplants?
For indoor use, a low‑odor, kelp‑only product such as GS Plant Foods Liquid Kelp Fertilizer or Bloom City’s Clean Kelp (available in quart and 128‑oz sizes) is ideal because they lack the strong fish smell and are safe for foliage sprays. If a nitrogen boost is needed, the deodorized Alaska Fish Emulsion (5‑1‑1) provides a mild scent and gentle nutrient profile suitable for houseplants when diluted to 2 Tbsp per gallon.
Why is OMRI certification important when selecting an organic kelp fertilizer?
OMRI certification confirms that the product meets strict organic standards, ensuring no synthetic chemicals or prohibited additives are present. This is crucial for gardeners who sell produce as organic or who follow certified organic gardening practices. Both GS Plant Foods Liquid Fish & Kelp and their pure kelp version carry OMRI listing, giving confidence that the fertilizer aligns with organic regulations.