10 Best Fish Fertilizer For Plants 2025 in the United States

Neptune's Harvest Fish & Seaweed Fertilizer 2-3-1 is a liquid fertilizer that combines fish and seaweed to provide essential nutrients for plant growth. The NPK ratio of 2-3-1 means it has 2% nitrogen, 3% phosphorus, and 1% potassium, which supports balanced plant growth, flowering, and root development. Its liquid form makes it easy to mix and apply using various methods such as hand watering, sprayers, or drip lines, making it versatile for different gardening needs.

One notable advantage is that it covers approximately 8000 square feet per gallon, making it cost-effective for larger areas. However, being a fish-based fertilizer, it may have a strong odor, which some users might find unpleasant. The fertilizer is designed to enhance plant growth, resulting in stronger, more colorful flowers and foliage, as well as more plentiful and fragrant blooms. It is suitable for vegetable gardens and decorative plants alike.

Users should consider the odor and the lack of explicit organic certification when deciding if this is the right product for them.

The GS Plant Foods OMRI Listed Fish & Kelp Fertilizer is an organic liquid fertilizer that combines fish and seaweed to promote plant growth. Its NPK ratio, while not explicitly stated, likely balances nutrients from both fish and kelp sources. The fertilizer is in liquid form, making it easy to mix with water and apply to various plants, including vegetables, trees, lawns, shrubs, and flowers.

Its organic certification ensures that it's safe for use in organic gardening and is environmentally friendly. The fertilizer helps improve soil health, plant color, and stress resistance, making plants more resilient to harsh weather conditions and enhancing their vitality. It is suitable for both home gardeners and commercial use, providing consistent and impressive results.

However, the product does have a strong odor, which might be off-putting for some users. Additionally, as it is a liquid, it requires careful measurement and application to avoid overfeeding plants. Despite these minor drawbacks, the GS Plant Foods Fish & Kelp Fertilizer is a reliable choice for those looking to boost their garden's health naturally and sustainably.

The ALASKA Fish Emulsion Fertilizer 5-1-1 concentrate is a versatile liquid fertilizer suitable for a variety of plants, including house plants, fruits, vegetables, ornamentals, and shade trees. Its 5-1-1 NPK ratio is beneficial for general plant growth, offering a higher nitrogen content which is ideal for leafy growth and robust plant health. As a liquid fertilizer, it can be easily mixed with water using the specified 1:10 mixing ratio, making it convenient for application through watering cans or sprayers. This is a significant advantage for users looking for a straightforward and quick application method.

However, a common drawback of fish emulsion fertilizers like this one is their odor. Fish-based fertilizers can emit a strong smell which might be off-putting for some users, particularly if used indoors. While the product description does not explicitly mention organic certification, fish emulsion fertilizers are typically considered a natural or organic option, but it's worth verifying if organic certification is crucial for your gardening practices.

The product's packaging includes two 1-gallon bottles, providing ample supply to cover a wide area or multiple plantings, which is great for those with larger gardens or multiple plants. Customer reviews are generally positive, with a rating of 4.4 out of 5 stars, suggesting satisfaction with its performance. Yet, some users might find the concentrated form requires careful mixing to avoid over-fertilization. The fertilizer's nutrient content is suitable for promoting vigorous plant growth, but those seeking a more balanced NPK ratio might need to look elsewhere.

In summary, the ALASKA Fish Emulsion Fertilizer is a solid choice for gardeners seeking a nitrogen-rich, easy-to-use liquid fertilizer, provided they can tolerate its strong fishy odor.