Taking a Closer Look at Seawater Farming

Seawater farming. Source: Euronews

Sea water farming is farming using water from the sea instead of fresh water.

There are, as we will see, many different types of seawater farming using different techniques.

Why This Solution?

Fresh water makes up only 3% of all water available on earth, and most of it is trapped in glaciers.

Using seawater would enable regions of the world where water isn’t available in huge quantities to farm and avoid drought and famine.

A lack of water causes important social and public health issues and prevents economic development.

Seawater farming is a first step toward solving these problems.

How Seawater Farming Works

Seaweed farming

Photo by Alexey Komissarov: Pexels

The first type of seawater farming is simply growing sea vegetables in the sea.

Many types of seaweed are edible. Increasing their role in the human (or animal) diet could help with the shift towards sustainable agriculture.

Indeed, seaweeds are grown directly in the sea. They don’t consume freshwater, they don’t take up space, and they don’t exhaust the soil either.

Genetic Technology

The second type of seawater farming is somewhat equivalent to the first one, except it concerns food that normally cannot grow in seawater.

Several startups are attempting to genetically modify rice or other plants so that they can be grown with seawater, or directly in the sea like seaweeds.

Salt takes a lot of energy and complexity for life to manage and regulate. Plants or animals that aren’t used to living in an environment righ in salt often die as a result.

Making more plants salt tolerant could help with growing them in the sea.

Desalination of Water

Desalination plant. Source: Wikipedia

There are several ways to filter out salt from water. Classic water desalination uses reverse osmosis. Reverse osmosis forces water through filters at very high pressure. Filters filter the salt and other impurities, making water available for consumption.

However, this type of desalination practice is costly in energy.

Several companies are working on a greenhouse that could be installed by the sea. The greenhouse would pump the seawater then use the sun to help it evaporate. The water is subsequently cooled down and goes to nourish the plants.

Recreating an Ecosystem

The last version of seawater farming concerns recreating a mini-ecosystem that uses and filters out the water.

First, the seawater is channelled into a fish farm. Once it’s packed with natural nutrients, the seawater continues its voyage to a mangrove farm. The mangrove tolerates saltwater and can split the water from the salt.

The leaves from the mangrove are available for human or animal consumption.

What Are the Challenges?

Scale and cost are the biggest challenges. Several of these projects are currently being tested in several countries.

While many of these projects work on a small scale, the high cost they entail means that it’s difficult to make them profitable, at least for now.

Will Seawater Farming Be Implemented in the Future?

It is highly likely.

As the worldwide population increases and the availability of freshwater decreases, seawater farming solves several problems at once, namely lack of food and lack of fresh water.

It will help communities living in dry areas to become independent and grow food on a reliable basis.


Seawater is farming using seawater.

Several solutions exist, from water desalination greenhouses to farming directly in the sea.

While seawater farming is in the research state currently, it will likely become a reliable solution to help make agriculture more sustainable while unlocking new sources of fresh water for dry areas.



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