How a Fish Might Grow Your Next Salad | Decoder

This is a seed. It doesn't look like much right now, but if you ... put it in the ground, give it some water, fight off invaders, and wait a little while... After a few weeks with a little luck, you might end up with a head of lettuce. That's a lot of work for a hundred calories.

But what if we had an easier way of doing things... One that didn’t require any soil, used much less water, and grew faster? One where food could actually grow itself? By 2050, the world's population is expected to reach almost 10 billion people. That's a lot more mouths to feed.

But, only 11 percent of land is even suitable for agriculture. So, farmers will have to turn to innovative and more efficient farming practices for a solution. One of the most promising is a method called aquaponics, which doesn't require any soil, and involves raising fish and plants together in a contained system.

There are several different setups you can use, but here's how the most popular method works. The process begins at the fish rearing tank. Here, highly adaptable fish like tilapia, are given plenty of fish food, which also leads to plenty of waste. The solid waste is filtered out by flowing water, but the water—which is still full of ammonia from the fish excrement—is mixed with special plastic pieces.

Naturally occurring bacteria grow on these surfaces, which helps convert the toxic ammonium in the water into nitrites and then nitrates. Nitrates are basically plant food. So, the nutrient-rich water flows out into the growing area, where seedlings on floating rafts can absorb the food directly through their roots. No soil required.

Above them, energy-efficient LED lights are adjusted to provide the optimal color spectrum. All of this comes together, helping the plants grow up to twice as fast as land crops. And because the plant roots purify the water, the cycle can start all over again. Commercial systems can yield up to 12 times as much produce per square foot as traditional farming methods.

Leafy greens like lettuce are the easiest crops to grow, but they often focus on more valuable herbs like basil and mint. Aquaponics is one of the most sustainable agricultural systems, but it still has a long way to go before becoming a go-to farming method. New developments are continuing to make the process more customizable, automated, and efficient than ever.

Who knows, in the future your salad might even be grown by a fish! What food would you grow in your aquaponic system? Let us know in the comments below.