If you’re gearing up for tomato season and want to give your garden a natural boost, there’s a surprisingly old-school gardening hack that could help you grow your best tomato crop yet—burying a fish head beneath each plant. While it might sound strange at first, this method has been used for generations and is backed by both tradition and science.
Fish heads are loaded with the kind of nutrients tomato plants love, including nitrogen, phosphorus, and potassium. According to research from Indonesia’s Environmental Science Master’s Program, fish heads contain 8.3% nitrogen, which promotes lush, green growth, 4.8% phosphorus to support strong roots and flowering, and 1.6% potassium to enhance the quality and taste of your fruit. But the real magic happens beneath the soil.
As the fish head decomposes, it creates a rich buffet for soil organisms like microbes, earthworms, and fungi, which break it down and gradually release nutrients right at the roots of your plant. This means your tomato plants get a steady, slow-release supply of essential elements without the risks associated with chemical fertilizers. This gardening method isn’t exactly new—Native American farmers used to bury a small fish under corn seeds as part of their “Three Sisters” planting technique, which also included beans and squash. While modern gardeners often skip the fish part, it was actually the powerhouse component that fueled the success of those companion plantings. Reviving this ancient trick not only honors tradition but also helps you create healthier, more fertile soil without relying on synthetic products. One of the biggest advantages of using fish heads is that they act as a long-term soil booster.
Unlike synthetic fertilizers that can overwhelm plants and even damage them with too much nitrogen at once, fish-based nutrients release slowly, making them safer and more effective over time. Fish scraps also include trace minerals like calcium and magnesium, which help plants build strong cell walls and fight off disease.
Plus, using leftovers from the kitchen reduces waste and puts every part of the fish to good use. You don’t need to catch your own fish to get started—just save heads and tails in a freezer bag over time or ask your local fishmonger if they have extras. When planting, dig a hole about 18 to 24 inches deep, drop the frozen fish head into the bottom, cover it with soil, and plant your tomato so that one-third of its stem is buried. Tomatoes can grow roots along their buried stem, making them stronger and more resilient. After planting, water thoroughly and apply mulch to help retain moisture and suppress weeds. One tip: don’t bury banana peels or eggshells in the same hole—they take too long to break down and could disrupt the soil. If raw fish isn’t available or you’re worried about attracting animals, there are still plenty of options. Canned sardines in water (not oil or seasoning) can work in a pinch, and commercial fish fertilizers are widely available and easy to use. Products like fish emulsion, fish hydrolysate, and fish meal are made from fish waste and provide all the benefits without the mess or odor. Fish emulsion is a liquid fertilizer made from fish offal, fish hydrolysate is a fermented product that retains more nutrients, and fish meal is a dry powder that’s easy to mix into the soil. If you’re into DIY projects and don’t mind a little smell, you can make your own fish emulsion at home. All you need are fish scraps, sawdust, unsulfured molasses, water, and a five-gallon bucket with a lid. Fill the bucket halfway with equal parts fish scraps and sawdust, add a cup of molasses, then top it off with water until everything is submerged. Stir it daily for about two weeks. After fermenting, strain the liquid and dilute it—one tablespoon per gallon of water—before applying it to your garden twice a week. While this method is highly effective, it’s not without risks. Raw fish can carry bacteria like salmonella or parasites, and if not buried deep enough, the smell may attract raccoons, rats, or stray pets. Some fish can contain heavy metals like mercury, so avoid using spoiled or questionable sources. To minimize risk, always bury the fish at least 18 inches deep and choose fresh, safe scraps. If in doubt, stick to store-bought fish fertilizers for peace of mind. In the end, burying fish heads under your tomato plants may not be the most glamorous gardening strategy, but it’s one of the most natural and effective ways to enrich your soil and encourage healthy, flavorful fruit. Whether you go the DIY route or prefer commercial alternatives, giving your tomatoes a fishy boost is a time-tested method your garden will appreciate. So next time you’re planting tomatoes, skip the synthetic stuff and go with a solution that’s been working for centuries—your tomatoes will thank you.
