After the summer, fishermen on the West Coast go all out trolling for albacore tuna, filling their shelves and freezers with loins. The added benefit of breaking down your own fish is that the fish heads and tails you have left over go into my freezer for spring. When spring comes, I put one of those fish heads in the ground under each of my tomato plants. While that may sound awful, remember that a lot of the fertilizer you buy is fish fertilizer, made from the same stuff. Here’s why you should consider burying fish heads in your garden.

Plants need a mixture of nitrogen, phosphorus, and potassium to grow, flower, produce fruit, and set seed. This combination is known as NPK, and all fertilizers you buy will have a number on the front. For example, a 5-5-5 fertilizer is a balanced mix of equal parts nitrogen, phosphorus, and potassium. A 17-1-1 fertilizer is almost entirely nitrogen. Although plants always need all three elements to some extent, they benefit more from each element at different stages in their life cycle. Nitrogen is for stimulating green growth. Phosphorus is essential for root growth and flowering, and potassium contributes to fruit formation and fruit quality.

Tomatoes are fantastic at growing roots, so much so that when you plant tomatoes you should bury as much of the stem as possible because roots will grow anywhere outside of the stem. You can simply cut a branch off an existing tomato plant, stick it in the ground and it will grow roots. Tomatoes are so good at growing roots that the fertilizer we put on top of them or even in the hole may not reach the roots when it needs to.

On the other hand, a rotting fish head is full of nitrogen, calcium, and phosphorus, which is exactly what a tomato plant needs. If you bury it deep enough, it will start to rot around the time the roots meet it in the soil. This will result in a boost for your plant at exactly the time it needs it.