Comparison: Best Fish Fertilizer For Seedlings (Updated | Dec 1st)
If you’re starting seedlings this season, you know they need a gentle yet powerful boost to thrive—and that’s where fish fertilizer shines. But with so many options out there, how do you pick the best one? We’ve tested top-rated fish fertilizers to find which delivers the ideal balance of nutrients, smell control, and ease of use. Whether you’re growing veggies, herbs, or flowers, the right fish fertilizer can make all the difference. Let’s dive into the best choices to give your tiny greens a healthy, natural start.
- Best for vitamin-rich boost: CENTRAL GARDEN BRANDS 100099247 Fish Emul Fertilizer
- Best for omri certified blend: Alaska Fish Fertilizer OMRI Listed 5-1-1
- Best for vibrant bloom formula: Neptune’s Harvest Fish & Seaweed Fertilizer 2-3-1 (36 Ounce)
- Best for us salmon boost: Fish Emulsion Fertilizer
- Best for wintergreen deodorized: Alaska Fish Emulsion Fertilizer 5-1-1 Concentrate 1 Gallon (Packaging may vary)
- Best for odorless protein power: Neptune’s Harvest Fish Fertilizer 2-4-1
- Best for seedling root vitalizer: FoxFarm Bush Doctor Wholly Mackerel Fish Fertilizer
- Best for eco cold-pressed: 1 Gallon Organic Fish Emulsion Fertilizer for Plants – Ideal Liquid Fish Fertilizer for Plants
- Best for bone meal boost: Down To Earth All Natural Fertilizers Organic Fish Bone Meal – High Phosphorus Plant Food for Buds
- Best for cold-process rich: Neptune’s Harvest Fish Fertilizer 2-4-1
Product Comparison: Best Fish Fertilizer For Seedlings
CENTRAL GARDEN BRANDS 100099247 Fish Emul Fertilizer, 1 Quart
- Promotes healthy plant growth with 11 vitamins
- Can be used on all indoor and outdoor plants
- 100-percent organic
- Stimulates microorganisms
- Does not burn
Alaska Fish Fertilizer OMRI Listed 5-1-1, 115 oz
- Fish-based fertilizer for use in vegetable, fruit, and flower gardens
- Excellent for use on flowers, trees, and other plants
- OMRI listed
- For organic gardening
- Great for all indoor and outdoor plants
- NPK 5-1-1 fish emulsion fertilizer
- Fish has been used as a natural source of plant nutrients for centuries
- Easy to use, just mix with water
Neptune’s Harvest Fish & Seaweed Fertilizer 2-3-1 (36 Ounce)
- Grow a beautiful vegetable garden
- Flowers and foliage will be stronger and more colorful
- Blooms will be more plentiful, fragrant and longer lasting
- Easy to mix and apply by hand, sprayer, or drip line
Fish Emulsion Fertilizer, Complete Fish Emulsion Plant Food, 8 oz (250mL)
- Complete fish fertilizer for thriving plants
- Helps growth with natural harvest salmon nutrients
- Easy-to-follow care instructions included
- Made in the USA
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
Neptune’s Harvest Fish Fertilizer 2-4-1, 18 Ounce
- Neptune’s Harvest is an organic fertilizer made from fresh north Atlantic fish
- It is made by a unique cold process that protects the vitamins, amino acids, enzymes and growth hormones
- It also contains all the micro and macro nutrients naturally found in fish
- Unlike fish emulsions, Neptune’s Harvest retains the fish proteins and oils and has no unpleasant odor
FoxFarm Bush Doctor Wholly Mackerel Fish Fertilizer, Fx14113 – Liquid Plant Nutrient for Seedlings, Transplants, and Vegetative Growth – NPK 3-1-0 (Pint)
- SEEDLING & TRANSPLANT VITALIZER: This fish plant food promotes root strength, making it perfect for nurturing young seedlings & transplanted plants. Its fast-acting formula ensures plants receive rapid nutrition, helping them establish robust foliage
- EFFECTIVE ROOT DRENCH APPLICATION: This fish fertilizer for plants is for root drench applications, allowing nutrient absorption through the roots. It ensures deeper nutrient penetration, enhancing plant resilience, during early growth stages
- ESSENTIAL GROWTH INGREDIENTS: Made with fish protein hydrolysate, molasses, and kelp, this fish emulsion fertilizer provides a mix of nutrients. Fish protein provides essential amino acids, molasses gives soil microbes, and kelp supports plane health
- EASY MIX FOR THRIVING PLANTS: Using fish plant fertilizer is a breeze, simply mix 1 tablespoon per gallon of fresh water and drench the soil thoroughly. For optimal results, apply every other week throughout the vegetative cycle until early fruiting
- TRUSTED FOXFARM QUALITY: From a brand known for sustainable and effective gardening solutions, Our fish hydrolysate fertilizer is a high-quality option for feeding your plants. Trust FoxFarm for products that support lively gardens and vibrant plants
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!
Down To Earth All Natural Fertilizers Organic Fish Bone Meal – High Phosphorus Plant Food for Buds, Bulbs, Blooms, Flower Beds 4-12-0, 5 lb
- Water-Soluble Formula – Easily dissolves in water for quick absorption and efficient nutrient delivery directly to the root zone
- Targets Root Development – Formulated to enhance root growth, improving plant stability, nutrient uptake, and drought resistance
- Fast-Acting Nutrients – Provides immediate access to essential nutrients like nitrogen, phosphorus, and potassium where roots need them most.
- Ideal for Transplants & Seedlings – Great for jumpstarting young plants or helping transplants establish quickly in new soil.
- Improves Soil-Root Interaction – Encourages a healthy rhizosphere, boosting microbial activity and root-zone nutrient cycling.
Neptune’s Harvest Fish Fertilizer 2-4-1, 36 Ounce
- Neptune’s Harvest is an organic fertilizer made from fresh north Atlantic fish
- It is made by a unique cold process that protects the vitamins, amino acids, enzymes and growth hormones
- It also contains all the micro and macro nutrients naturally found in fish
- Unlike fish emulsions, Neptune’s Harvest retains the fish proteins and oils and has no unpleasant odor
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 should I look for in a fish fertilizer for seedlings?
Choose a formula with a low‑to‑moderate NPK ratio (around 2‑3‑1) that supplies steady nitrogen without overwhelming delicate roots. Look for added micronutrients, kelp or molasses that support microbial activity and root development. A gentle, non‑burning blend is essential for young plants that are sensitive to fertilizer strength.
How does the NPK ratio affect seedling growth?
A lower nitrogen (N) level prevents rapid, weak foliage growth, while sufficient phosphorus (P) encourages strong root systems and potassium (K) supports overall plant vigor. Ratios like 2‑3‑1 or 5‑1‑1 deliver balanced nutrition ideal for seedlings and transplants. Higher ratios can cause leaf scorch or stunt root development in young plants.
Which product offers the best value for large garden use?
The Alaska Fish Emulsion 5‑1‑1 Concentrate (1 gallon) provides a high volume at a low cost per ounce and includes a deodorized wintergreen scent, making it economical for extensive beds. Its 5‑1‑1 ratio suits both vegetables and ornamental plants, and the large container reduces the frequency of repurchasing. For gardeners who prefer a smaller, ready‑to‑use bottle, the 1‑quart Central Garden Brands option is convenient but less cost‑effective per application.
Are there any odor considerations when choosing a fish fertilizer?
Traditional fish emulsions can have a strong fishy smell, which some gardeners find off‑putting. Products like Neptune’s Harvest 2‑4‑1 and the FoxFarm Wholly Mackerel use a cold‑process that retains nutrients while minimizing odor, making them more pleasant for indoor or patio use. If odor is a primary concern, look for “deodorized” or “no‑odor” labels such as Alaska Fish Emulsion with natural wintergreen.
How do organic certifications like OMRI impact my choice?
An OMRI listing confirms the product meets organic farming standards, allowing use in certified organic gardens without risking compliance issues. Both Alaska Fish Fertilizer OMRI Listed 5‑1‑1 and Down To Earth Fish Bone Meal carry this certification, giving peace of mind for growers who sell organic produce. Certified products may also undergo stricter testing for contaminants, adding an extra layer of safety.
What are the benefits of adding kelp or molasses to fish fertilizer?
Kelp supplies natural plant hormones and trace minerals that boost stress tolerance and improve overall vigor, while molasses feeds beneficial soil microbes, enhancing nutrient cycling. FoxFarm Wholly Mackerel combines fish protein hydrolysate with kelp and molasses for a synergistic effect on seedling root strength and foliage development. These additives can accelerate early growth compared to plain fish emulsion alone.
How do liquid versus concentrated formulas compare for seedling applications?
Liquid fertilizers like the 1‑quart Central Garden Brands are ready to dilute and apply, reducing the risk of over‑concentration on fragile seedlings. Concentrated formulas such as the 1‑gallon Alaska Fish Emulsion require careful mixing but are more economical for large areas and allow precise dosage adjustments. For small indoor seedling trays, a pre‑diluted liquid is often more convenient, whereas outdoor beds benefit from the flexibility of a concentrate.