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.

Neptune's Harvest Fish Fertilizer is a liquid organic fertilizer with an NPK ratio of 2-4-1, providing a balanced mix of nitrogen, phosphorus, and potassium to support healthy plant growth. It is made from fresh North Atlantic fish through a cold process that preserves important nutrients including vitamins, amino acids, enzymes, and growth hormones beneficial to plants. A notable feature is that it retains fish proteins and oils, unlike typical fish emulsions, resulting in a fertilizer with little to no unpleasant fishy odor, making it more user-friendly for home gardeners.

This organic product contains a full range of micro and macro nutrients naturally found in fish, supporting both soil and plant health. It comes as a 36-ounce liquid that is easy to dilute and apply either through watering or foliar feeding. The coverage is medium-sized, so larger gardens might require multiple bottles. It is well-liked among gardeners looking for a natural, odor-free option to boost their plants' nutrition without synthetic chemicals.