Comparison: Best Applying Fish Fertilizer (Updated | Dec 1st)

Indoor plants often need a milder formulation to avoid excess moisture and strong odors, so a low‑volume, non‑burning emulsion like the Central Garden Brands 1‑Quart or the Alaska 5‑1‑1 concentrate works well. Outdoor gardens can handle higher concentrations and larger volumes, making 1‑gallon options such as the Organic Fish Emulsion or Neptune’s Harvest 2‑3‑1 ideal. Look for products labeled as safe for all plant types and check if they include additives like seaweed for added vigor.

The ratios range from 5‑1‑1 (Alaska Fish Emulsion) to 2‑3‑1 (Neptune’s Harvest and the 1‑gallon organic emulsion), affecting the balance of nitrogen for foliage growth versus phosphorus and potassium for root and fruit development. A higher nitrogen ratio promotes leafy growth, while a balanced 2‑3‑1 mix supports flowering and fruiting. Choose the ratio that matches your garden’s current stage—leafy greens benefit from higher nitrogen, whereas fruiting plants thrive on more phosphorus and potassium.

The Alaska Fish Fertilizer 5‑1‑1, GS Plant Foods Fish & Kelp Fertilizer, and GS Plant Foods Organic Liquid Fish Fertilizer carry OMRI certification. This indicates the products meet strict organic standards, making them safe for use in certified organic gardens and reducing the risk of harmful synthetic residues. For growers who sell produce as organic, using OMRI‑listed fertilizers helps maintain compliance with certification bodies.

Larger containers like the 1‑gallon Organic Fish Emulsion or the 115‑oz Alaska Fish Fertilizer provide a lower cost per ounce compared with 8‑oz or 18‑oz bottles, but they require dilution before use. Concentrated formulas (e.g., 5‑1‑1) let you stretch each gallon over many applications, further reducing expense. Calculate the total cost per garden‑season by dividing the price by the number of recommended feedings for each size.

All real fish emulsion products will have a noticeable fishy smell, especially the 1‑gallon organic emulsion and Bloom City Wild Fish Fertilizer, which proudly advertise their scent. To reduce odor, apply the fertilizer early in the morning when temperatures are cooler and avoid spraying in enclosed spaces. Diluting the product according to the label also lessens the intensity of the smell while still delivering nutrients.

The 1‑gallon Organic Fish Emulsion (2‑3‑1) provides a high nutrient density, low N‑P‑K ratio suitable for a wide range of crops, and a competitive price per gallon, making it cost‑effective for extensive beds. The Alaska 115‑oz 5‑1‑1 fertilizer is another strong contender, offering OMRI certification and a balanced nutrient profile at a bulk size. Both options reduce the need for frequent repurchasing compared with smaller bottles.

Kelp and seaweed contain natural plant hormones, micronutrients, and trace minerals that boost root development, stress tolerance, and overall vigor. Products such as GS Plant Foods Fish & Kelp Fertilizer combine fish nutrients with kelp to enhance nutrient uptake and improve soil microbial activity. This synergy can lead to stronger stems, richer foliage, and higher yields, especially in nutrient‑poor soils.

Most liquid fish emulsions can be mixed with water and applied as a soil drench, foliar spray, or through drip irrigation; the Central Garden Brands product suggests a 1‑tablespoon per gallon ratio for indoor pots. For larger volumes like the 1‑gallon Organic Emulsion, a 1‑to‑2‑percent solution works well for both soil and foliar feeding. Always follow the label’s timing—typically every 2‑3 weeks for vegetables and every 4‑6 weeks for ornamental plants—to avoid over‑fertilizing.