Best Fish Fertilizer For Plants: 10 Liquid Options Compared

#1 · Best Overall

1. Neptune's Harvest Fish & Seaweed

• Form: Liquid
• Weight: 2.3 lb

Best for: Fish-and-seaweed all-purpose feeding.

Why it ranks #1: Its 2-3-1 liquid blends 75% fish and 25% seaweed, with listed uses spanning vegetables, flowers, fruit, trees, lawns, and indoor plants.

A 75% fish and 25% seaweed blend gives this liquid fertilizer a two-source formula for feeding vegetables, flowers, fruit, trees, lawns, and indoor plants. Its 2-3-1 nutrient balance makes it an all-purpose option for gardeners who want one product spanning several plant types and growing spaces.

The liquid form supports routine feeding across indoor and outdoor plants, while the fish-and-seaweed combination brings both ingredients into one formula. That broad listed use can simplify choosing plant food when a garden includes vegetables, flowers, trees, and lawn areas. The 36-ounce bottle offers a larger supply than a small-format bottle, and the directions say to shake well before use. Keep it out of children's reach, as stated in the safety information.

Skip it if you want a fish-only formula; Neptune's Harvest Fish Fertilizer 2-4-1 offers fish hydrolysate without the listed seaweed blend.

Gardeners feeding a mix of vegetables, flowers, trees, lawn, and indoor plants can use this broad-use fish-and-seaweed formula. Choose it when the combined ingredients suit your routine; it is not the fish-only choice in this roundup.

Listed on Amazon as: Neptune's Harvest Fish & Seaweed Liquid Fertilizer (2-3-1) – 36oz Bottle – Plant Food for Garden – Indoor & Outdoor Organic Plant Fertilizer for Vegetables, Flowers, Fruit, Trees & Lawns

#2 · Organic Production

2. GS Plant Foods Liquid Fish

• Form: Liquid
• Weight: 8.4 lb

Best for: OMRI-listed gallon concentrate.

Why it ranks #2: This one-gallon hydrolyzed fish concentrate is OMRI Listed for organic production and specifies a balanced 2-3-1 analysis.

OMRI listing for organic production is the defining credential of this gallon-size hydrolyzed fish fertilizer, giving organic growers a product identified as suitable under OMRI and NOP standards. Its 2-3-1 analysis also provides a balanced nutrient profile for gardens, lawns, and container growing.

The 1-gallon liquid concentrate can serve gardeners feeding multiple areas, including garden beds, lawns, and containers, while the broad listed suitability supports a varied planting plan. Hydrolyzed fish supplies nitrogen, phosphorus, and potassium in a 2-3-1 ratio, and naturally occurring organic compounds are described as supporting soil vitality and consistent nutrition through the growing season. Its OMRI listing is relevant for organic production, making it a fit for growers prioritizing that standard.

Skip it if you need a small bottle for occasional feeding; TPS NUTRIENTS Fish Emulsion Fertilizer comes in an 8-ounce size.

Organic growers tending gardens, lawns, or containers can choose this gallon-size OMRI-listed concentrate for 2-3-1 feeding. Its larger container makes most sense when several areas need fertilizer, rather than for an occasional small-pot routine.

Listed on Amazon as: GS Plant Foods Liquid Fish Fertilizer – Organic Material Review Institute Listed (1 Gallon) – Natural Hydrolyzed Fish Fertilizer for Gardens, Lawns & Container Growing

#3 · Fish-Only Formula

3. Neptune's Harvest Fish Fertilizer

• Form: Liquid
• Weight: 0.51 kg

Best for: Cold-processed fish hydrolysate.

Why it ranks #3: The organic liquid fish hydrolysate has a 2-4-1 analysis and is listed for vegetables, flowers, fruit, trees, grass, and indoor plants.

A cold process that protects vitamins, amino acids, enzymes, and growth hormones is the defining feature of this 2-4-1 fish hydrolysate. Sourced from North Atlantic Ocean fish rather than lake, farmed, or river fish, it is listed for vegetables, flowers, fruit, trees, grass, and indoor plants.

The cold-processing description gives buyers a specific reason to choose this fish formula: the process is stated to protect several naturally occurring components. Its 2-4-1 analysis sets it apart from 2-3-1 options, which matters when selecting a nutrient balance for a feeding plan. The listed applications span lawns, vegetables, flowers, fruit, trees, and indoor plants, so a single pint can serve varied plantings. The liquid format supports mixing and application as part of routine care.

Skip it if you need a gallon for broad, repeated feeding; GS Plant Foods Liquid Fish Fertilizer is listed in a 1-gallon container.

Choose this pint of cold-processed fish hydrolysate when its 2-4-1 ratio and stated North Atlantic sourcing fit your plan. It covers many plant types, but the pint format is better suited to smaller routines than gallon-scale use.

Listed on Amazon as: Neptune's Harvest Fish Fertilizer (2-4-1) – Organic Liquid Plant Fertilizer – Fish Hydrolysate for Vegetables, Flowers, Fruit, Trees, Grass – Indoor and Outdoor Plant Food (Pint)

#4 · Large Garden Bottle

4. The Grow Co Organic Fish

• Form: Liquid
• Weight: 2.3 lb

Best for: Cold-pressed gallon garden supply.

Why it ranks #4: Its one-gallon organic hydrolyzed fish formula is listed for vegetables, fruits, and flowers, with directions to mix 1 ounce per gallon of water.

Fresh, 100% cold-pressed refining is the key distinction of this gallon-size organic fish emulsion, which is described as retaining nutrients, vitamins, and amino acids. Its listed 2-3-1 formula and use for vegetables, fruits, and flowers suit gardeners planning regular feeding across edible and ornamental beds.

The concentrate is mixed with water before application, and the supplied rate is 1 ounce, or 2 tablespoons, per gallon, applied every 1–2 weeks. That schedule and the gallon format support planned feeding across a larger garden, while the listed indoor and outdoor use broadens where it can be applied. The fish emulsion is made from sustainably sourced fish, using parts that would otherwise go to waste. Its 2-3-1 analysis gives buyers a clear nutrient profile.

Skip it if you want ready-to-use fertilizer without dilution; Heirloom Founder's Fish Fertilizer also requires mixing, so choose a product whose supplied directions suit your routine.

Gardeners feeding vegetables, fruit, and flowers on a regular schedule can use this gallon-size 2-3-1 concentrate indoors or out. It fits buyers comfortable measuring and mixing fertilizer with water before each application.

Listed on Amazon as: Organic Fish Fertilizer for Vegetable Garden, Fruits, and Flowers, 1 Gallon

#5 · Defined 5-1-1 Formula

5. ferti-lome Fish Emulsion

• Form: Liquid
• Weight: 1.2 lb

Best for: Measured 5-1-1 fish feeding.

Why it ranks #5: The 5-1-1 analysis is specified, along with directions to mix 1–2 tablespoons per gallon for plants and 4 tablespoons for trees.

A stated 5-1-1 analysis and specific mixing rates make this fish emulsion a clearly measured feeding option. For plants, the directions call for 1–2 tablespoons per gallon of water; trees have a separate rate, giving gardeners a practical starting point for preparing feeds across different plant types.

The formula derives from fish soluble and is listed for indoor and outdoor use on plants and trees, so one bottle can serve more than one setting. Mixing with water and using any convenient application method gives flexibility in how it is applied. The supplied plant rate is 1–2 tablespoons per gallon, while trees use 4 tablespoons per gallon. Its 5-1-1 balance emphasizes a different nutrient ratio from 2-3-1 products, making the analysis worth matching to your plan.

Skip it if you want a 2-3-1 fish-and-seaweed blend; Neptune's Harvest Fish & Seaweed Liquid Fertilizer uses that listed ratio.

Gardeners who want a fish-derived 5-1-1 product with stated dilution rates for plants and trees can use this option indoors or out. Its nutrient ratio is the main fit consideration when comparing feeding plans.

Listed on Amazon as: Fertilome (10611) Fish Emulsion Fertilizer 5-1-1, 16 oz

#6

6. Heirloom Founder's Fish Fertilizer

• Form: Liquid
• Weight: 4 oz

Best for: Rose and tomato soil feeding.

Why it ranks #6: This 32-fluid-ounce fish emulsion is positioned for roses and tomatoes, and its listing provides soil-mixing directions and feeding intervals.

A formula identified as a best choice for roses and tomatoes gives this fish emulsion a focused garden role. Its directions specify 4 ounces per gallon of water for soil application, with that gallon of solution stated to cover two to three roses, making preparation easier to plan.

The soil-mixing directions give rose growers a concrete application workflow: prepare one gallon of solution from 4 ounces of fertilizer, enough for two to three roses. Listed intervals differ by setting, with in-ground plants fed every 4–6 weeks and container plants every 3–4 weeks. The organic liquid emulsion is also presented as beneficial to soil organisms and nutrient reception. These details make it especially relevant to rose and tomato growers rather than gardeners seeking only a general-purpose label.

Skip it if you need a fertilizer explicitly listed for lawns and trees; Neptune's Harvest Fish Fertilizer 2-4-1 names both uses.

Rose and tomato growers who prefer measured soil feeding can use the stated dilution and schedule to plan applications. Its directions are particularly useful for roses, while gardeners seeking broad lawn or tree coverage have other listed options.

Listed on Amazon as: Heirloom Founder's Fish Fertilizer, Liquid Plant Food, 32 Fl Oz

#7

7. Mandea Alaska Fish Fertilizer

• Form: Liquid
• Weight: 1.5 lb

Best for: Hydroponic and organic growers.

Why it ranks #7: The 946 mL liquid is described for hydroponic and organic gardening and a wide range of plants, though its listing gives no NPK ratio.

Compatibility with both hydroponic and organic gardening distinguishes this liquid fish fertilizer, giving growers in either setup a stated option for supporting plant growth. The 946 ml bottle is described as suitable for a wide range of plants, with a liquid form intended for measuring and mixing.

The liquid formula is presented for precise measuring and mixing, which lets growers prepare feed for their chosen application rather than handling a dry product. Its stated hydroponic and organic gardening suitability spans two growing approaches, while the broad plant-use description accommodates varied crops. The 946 ml bottle supplies a useful quantity for ongoing routines. Store it in a cool, dry place away from heat and open flames, and keep it away from children and pets.

Skip it if you want an explicitly OMRI-listed fertilizer for organic production; GS Plant Foods Liquid Fish Fertilizer carries that listed status.

Hydroponic and organic gardeners seeking a liquid fertilizer for varied plants can consider this 946 ml option. Its stated uses are broad, but buyers should weigh the included California Proposition 65 warning before choosing it.

Listed on Amazon as: FERTILIZ ALASKA FISH QT

#8

8. TPS Nutrients Fish Emulsion

• Form: Liquid

Best for: Compact indoor-and-outdoor feeding.

Why it ranks #8: This 8-ounce liquid fish emulsion is intended for indoor and outdoor gardens, with listed support for roots, foliage, and vegetable crops.

Root-strength support is the clearest focus of this 8-ounce liquid salmon supplement, which also promotes foliage and steady plant growth. Its stated use for indoor and outdoor gardens makes it a compact option for gardeners feeding vegetables alongside other plants without needing a formula limited to one setting.

The product description connects stronger roots with improved nutrient and water uptake, giving root development a practical role beyond foliage growth. It also promotes steady leaf and stem development, which suits gardeners seeking balanced visible growth. Its liquid form is for indoor and outdoor gardens, while the 8-ounce size keeps the package compact for smaller feeding routines. Directions are included with the product, and the safety information calls for protective gloves and eyewear during handling.

Skip it if you need gallon-size supply for repeated broad-area feeding; GS Plant Foods Liquid Fish Fertilizer is listed in a 1-gallon container.

Choose this for a small indoor or outdoor garden where root support and steady foliage development are priorities. Its 8-ounce bottle suits a compact routine, but gardeners managing larger areas may prefer a gallon-size product.

Listed on Amazon as: Fish Emulsion Fertilizer – Liquid Salmon Supplement for Plants, 8 oz

#9

9. TPS Nutrients Fish and Seaweed

• Form: Liquid
• Weight: 8 oz

Best for: Flexible watering-can feeding.

Why it ranks #9: The 8-ounce fish-and-seaweed liquid suits indoor and outdoor plants, containers, gardens, and raised beds, but the listing gives no NPK ratio.

Compatibility with watering cans, hose-end sprayers, and feeding schedules gives this fish-and-seaweed liquid several ways to fit into garden routines. The 8-ounce formula is listed for indoor and outdoor plants, including containers, gardens, and raised beds, with strong roots and healthy foliage as its stated goals.

The choice of watering can or hose-end sprayer lets gardeners use the application method that suits their setup, while the liquid format fits scheduled feeding. Its listed coverage of containers, gardens, and raised beds bridges small and larger planting spaces, indoors or out. The fish-and-seaweed formula is presented as supporting roots, foliage, nutrient uptake, and overall plant vitality. At 8 ounces, it is a compact option for a limited routine rather than a gallon supply.

Skip it if you need a gallon supply for regular feeding across many plants; The Grow Co Organic Fish Fertilizer is sold in a 1-gallon size.

This suits gardeners who want fish-and-seaweed feeding across containers, beds, and indoor plants, with watering-can or hose-end application. The 8-ounce size is the key boundary for larger gardens or repeated whole-garden treatments.

Listed on Amazon as: Fish and Seaweed Fertilizer – Liquid Plant Food for Healthy Growth & Strong Root Development, 8 oz (250mL)

#10

10. Lilly Miller Alaska Fish Fertilizer

• Form: Liquid
• Weight: 16 oz

Best for: Two-pack 5-1-1 concentrate.

Why it ranks #10: This listing identifies a 5-1-1 concentrate in a two-pack of quart bottles, but provides little additional information about its uses or directions.

Two quart bottles of 5-1-1 concentrate give this Alaska fish fertilizer a useful format for gardeners who want a multi-bottle supply. Its listed nutrient ratio identifies it as a higher-nitrogen option than 2-3-1 formulas, so the analysis is central to deciding whether it matches a feeding plan.

The two-pack supplies a combined two quart containers of liquid concentrate, offering a reserve for ongoing garden use rather than a single bottle. Its 5-1-1 analysis provides a clear nutrient profile for comparison with other fish fertilizers in the roundup. Because the supplied product details do not specify application rates or plant types, buyers should rely on the product directions for preparation and use. This option fits shoppers who have already decided that a 5-1-1 concentrate suits their routine.

Skip it if you need stated mixing rates before choosing a product; ferti-lome Fish Emulsion Fertilizer provides separate directions for plants and trees.

This two-pack suits gardeners seeking quart containers of 5-1-1 Alaska fish concentrate for an established feeding routine. The supplied details leave application rates and target plants unspecified, so consult its directions before preparing or applying it.

Listed on Amazon as: Lilly Miller Alaska Fish Fertilizer 5-1-1 Concentrate 1 Quart (2-Pack)