Fish emulsion (FE) is a fast-acting, organic liquid fertilizer derived from the byproducts of the fishing industry, making efficient use of natural resources. This thick, concentrated product is naturally rich in nitrogen, often having a nutrient ratio around 5-1-1 or 4-1-1, which promotes vigorous leaf and stem growth. Because it is highly concentrated, fish emulsion must always be diluted with water before application to prevent fertilizer burn. The following instructions provide clear dilution ratios and application methods to ensure plants receive the proper nourishment.
Standard Dilution Ratios for Soil Drench
For established, healthy, and mature plants, the standard dilution rate for a soil drench application is typically one ounce of fish emulsion concentrate per gallon of water. This equates to approximately two tablespoons mixed into one gallon of water, a common recommendation found on many commercial labels. This ratio provides a consistent nutrient dose for plants during their active growth phase. The diluted mixture is applied directly to the soil at the base of the plant, allowing the nutrients to be absorbed by the root system.
This standard concentration is suitable for most vegetables, annuals, and perennials that are actively growing. Applying the fertilizer as a soil drench ensures that the beneficial organic compounds are broken down by soil microorganisms, which converts them into readily available nutrients for the plant. Always shake the concentrated bottle well before measuring, as the thick emulsion tends to separate upon standing.
Some heavy-feeding plants, such as large tomatoes or zucchini, or plants in poor soil conditions may benefit from a slightly stronger mix, but it is safer to increase the frequency of application rather than the concentration. A slightly stronger mix would involve using up to three tablespoons per gallon for specific heavy feeders like roses. Always begin with the lowest recommended rate and observe your plants’ response before increasing the concentration or frequency.
Specialized Ratios for Plant Stage and Method
Deviating from the standard soil drench ratio is necessary when treating delicate plants or employing different application techniques like foliar feeding. For young, tender seedlings or recently transplanted plants, the standard concentration is too strong and can cause fertilizer burn. A weaker ratio is required to protect their developing root systems and foliage.
When feeding seedlings that have developed their first true leaves, it is best to use a half-strength or even quarter-strength solution. This translates to using about one to two teaspoons of fish emulsion per gallon of water, providing a gentle nutrient boost. This low concentration prevents the buildup of salts in the potting mix, which can dehydrate and damage the fragile roots.
Foliar feeding, which involves spraying the diluted solution directly onto the leaves, requires a significantly lighter ratio for effective absorption and to avoid leaf scorching. For foliar applications, mix only one to two teaspoons of fish emulsion per gallon of water. Applying a fine mist to the leaves allows for rapid nutrient uptake, bypassing the soil system entirely, making it ideal for a quick green-up.
Application Frequency and Timing
Once the correct dilution ratio is mixed, the frequency and timing of application depend largely on the plant’s growth stage and its specific nutrient needs. For most actively growing plants, a regular feeding schedule of every two to four weeks is effective for consistent nourishment. Since fish emulsion is a water-soluble fertilizer, its nutrients are immediately available to the plant and are not designed for long-term slow release.
Plants that are considered heavy feeders, such as corn, leafy greens, or container plants, generally require more frequent applications, often every seven to fourteen days. Container plants, in particular, need more frequent feeding because nutrients tend to leach out quickly with regular watering. Conversely, root crops like carrots or radishes benefit from less nitrogen, so you may apply a half-strength solution or feed them less often to encourage root growth over excessive foliage.
Timing the application is also important for maximizing nutrient uptake and minimizing plant stress. The best time to apply the diluted fish emulsion is during the cooler parts of the day, such as early morning or late afternoon. Applying fertilizer in the intense midday sun can stress the plant and increase the risk of leaf burn, especially with foliar sprays.
Safe Handling and Storage
Fish emulsion is characterized by a strong, distinct odor. To help mitigate the odor when applying outdoors, you can use deodorized versions of the product, but the smell typically dissipates within a day or two after application. Be aware that the odor can sometimes attract animals like raccoons, so consider this when applying it to container plants on a patio.
Proper storage is necessary to maintain the product’s efficacy and prevent accidental exposure. The concentrated fish emulsion, when stored in its original sealed container in a cool, dark location, can last indefinitely. However, any diluted solution of fish emulsion should not be stored and must be used immediately after mixing. The organic materials in the diluted mixture will begin to break down rapidly, leading to an unpleasant odor and a reduction in nutrient quality.
To prevent fertilizer burn, always ensure the fish emulsion is properly diluted and avoid applying the solution to dry soil. Concentrated fish emulsion can cause skin and serious eye irritation, so it is wise to wear safety glasses and neoprene or PVC gloves when handling the product. Should a spill occur, contain and clean up the material, and you can use a bleach or pine oil-based cleaner to help remove any residual odor.