by Valentina Lagomarsino
figures by Rebecca Senft

In the year 600 B.C.E., the climate was arid and dry along the Euphrates River in Western Asia, but there were lush gardens climbing up the walls of the metropolis, Babylon. It is believed that the Hanging Gardens of Babylon were surviving through a pulley-system of water from the river, a technique of agricultural that today is known as hydroponics. More specifically, hydroponics is the method of farming where plants can be grown in nutrient-fortified water, instead of in soil. Given concerns of feeding a growing human population in a changing climate, scientists believe hydroponic technology may be able to mitigate impending food shortages. 

The need for innovative agriculture 

The United Nations (UN) has projected the global population to reach nearly 10 billion people by 2050, with “roughly 83 million people being added to the world’s population each year until then.” In 2019 alone, an estimated 124 million people faced acute food shortages from climate-related events such as flooding, irregular rains, droughts, and high temperatures. Given that hydroponics can grow food in a controlled environment, with less water and in higher yields, the Food and Agriculture Organization of the United Nations has been implementing hydroponic farming in areas of the world that suffer from food shortages. There are currently ongoing projects to establish large hydroponic farms in  Latin American and African countries

The technology used in hydroponic systems being implemented in developing countries around the world are largely based off hydroponic systems that were designed at NASA. In the late 20th century, physicists and biologists got together to figure out a way to grow food in one of the starkest climate known to humans: space. Aerospace plant physiologists at NASA began experimenting with growing plants on the International Space Station using hydroponics technology because it requires less space and less resources than conventional farming. After extensive tests, astronauts ate the first space-grown leafy vegetables in 2015. How did NASA get the idea to use this technology in space? It was from a century of work by scientists who found that plants were surviving–and thriving–while being grown in water. 

Invention of modern day hydroponics

In the 19th century, a German botanist at the University of Wurzburg, Julius Sachs, dedicated his career to understanding the essential elements that plants need to survive. By examining differences between plants grown in soil and those grown in water, Sachs found that plants did not need to grow in soil but only needed the nutrients that are derived from microorganisms that live in the soil. In 1860, Sachs published the “nutrient solution” formula for growing plants in water, which set the foundation for modern day hydroponic technology (Figure 1). 

Figure 1: Nutrient Solution. Plants obtain 3 nutrients from the air–carbon, hydrogen, and oxygen–and 13 nutrients from supplemented water: nitrogen, phosphorous, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, boron, chlorine, and molybdate.

In 1937, an American scientist, Dr. W.E. Gericke described how this method of growing plants could be used for agricultural purposes to produce large amounts of crops. Gericke and others demonstrated that the fluid dynamics of water changed the architecture of plant roots, which allowed them to uptake nutrients more efficiently than plants grown in soil, causing them to grow larger in a shorter amount of time. Since then, scientists have optimized the nutrient solution, a total of 13 macronutrients and micronutrients, that are added to water for hydroponic farming (Figure 1).

Hydroponic systems today are very sophisticated; there are systems that will monitor the level of nutrients pH, and temperature of the water, and even the amount of light the plants are receiving. There are three main types of hydroponic systems: a nutrient film technique, an Ebb and Flow System, and a Wick system (Figure 2). A nutrient film hydroponic technique involves plants being grown in a grow tray that it slightly angled and positioned above a reservoir filled with the water-nutrient mix. This allows a thin stream of water to flow across plant roots, allowing the plants to have sufficient water, nutrients and aeration, and then drained back into the reservoir. The nutrient film technique is the most common hydroponic system used today. Plenty and Bowery, two of the largest hydroponic farms in the US, use nutrient film techniques to grow lettuce, spinach and other leafy greens. The Ebb and Flow technique allows plants to be flooded with the nutrient-rich water, and after the plant roots uptake nutrients, water is actively drained back into a reservoir to be reused. Finally, a hydroponic wick system is the simplest of all, as nutrients are passively given to the plant from a wick or piece of string running up to the plant from the water reservoir. In this system, plants are grown in an inert growing medium such as sand, rock, wool or clay balls that help anchor the plant roots. These different systems are interchangeable, but some systems may be better for growing different types of plants.

Figure 2: The three most common techniques for hydroponic farming. In all approaches, water is fortified with a nutrient solution is stored in a nutrient reservoir. The water is then actively pumped to the grow tray (panels A and B) or it is passively passed to the grow tray (panel C) through a wick. The plant roots grow thicker than those of plants grown in soil, which allow them to uptake nutrients more effectively.

The advantages of using any of these hydroponic systems are manifold. First, since there is no soil, there is no need to worry about having a plot of land, weeds, pathogens living in dirt, or treating the crops with pesticides. Water is also greatly conserved due to the nutrient reservoir because the same water can be reused over and over. Moreover, as most of these hydroponics farms are indoors, food can be produced all year round and even in the middle of a large city, like New York City. Given all of these benefits, we may begin to see more hydroponic farms sprouting up  across the US and around the world because this method of farming holds much promise to revolutionize agriculture by using less water and other resources. 

Hydroponics for a sustainable future

Given the need for more sustainable agriculture, there has been a rise in eco-friendly start-up companies around the world that are using hydroponic technology to produce crops on a large scale with a technique known as “Vertical Farming” (Figure 3). 

Vertical farms are buildings filled with countless levels of hydroponic systems (or nutrient film style planters), growing different crops in an indoor, controlled temperature environment (Figure 3). The largest vertical farm is being built in Dubai, covering 130,000 square feet of land and aiming to produce 6,000 pounds of food per day, “using 1/2500th the amount of water as an equivalent soil operation”. For a city that imports 85% of their food, this will greatly revolutionize the way the city eats. 

Figure 3: Vertical Farming. Vertical Farming is the term for large-scale hydroponic systems that are engineered to house thousands of square feet of growing systems, across many floors in a skyscraper-esque building.

While vertical farms hold a lot of promise, they are expensive to implement, technically difficult on a large scale, and the food produced from these systems is generally more expensive than equivalent soil grown food because of the high-energy costs of maintaining the systems. Even so, the Associated Press estimates that food produced by hydroponic technology in 2019 is worth $32 billion USD, and this is projected to grow at a rate of 5% per year until 2025.

While hydroponic technology may never replace conventional farming, it is breaking the paradigm of food production; we may see a new generation of modern farmers building green walls inside their houses or community centers to feed families with fresh produce grown all year round. 

Valentina Lagomarsino is a second-year PhD student in the Biological Biomedical Sciences program at Harvard University. 

Rebecca Senft is a fifth-year Program in Neuroscience PhD student at Harvard University who studies the circuitry and function of serotonin neurons in the mouse.

For More Information:

This article is part of our special edition on water. To read more, check out our special edition homepage

40 thoughts on “Hydroponics: The power of water to grow food

  1. I want to be able to grow food all year round, but I’m not sure how to be able to do that. It makes sense that hydroponics would be a good way to ensure that I can keep plans healthy all year round! I’ll have to make sure that I get the right nutrient systems so that I can keep things healthy.

  2. It’s good that you point out that hydroponic gardening allows you to grow food at any time of the year. I want to grow some tomatoes in my home, so I’m considering purchasing some hydroponic gardening supplies to help me do it. I’m going to look for a good company that can sell me some hydroponic gardening supplies.

    1. I am looking to buy hydroponic gardening supplies and how much it cost, which companies can I contact

  3. Hello,
    I like the blog information is very beneficial hydroponics the power of water to grow food. thank you for share this blog

  4. that great and very helpful to someone to grow plants any time of the year you want.
    i think we should do more research and come up with technologies like these to help people grow more and more food as the population is growing with alarming rate.

    if we want to stop people dying of hunger than the countries should put more fund in the research work to allow such innovations that help grow food anytime.

  5. The technology of hydroponic is good but costly for common people, I advise authorities, university, and other bodies to research on const reduction, so that it can be more popular. In the recent UN convention it is decided that UN will encourage for setting up Kitchen gardens, for solving future food crisis. If so, then UN and other companies shall think how to reduce cost of this hydroponic technique, so that poor cultivators can also adopt this technology and grow fruits and vegetables and fulfill UN dreams.

  6. Leafy greens will not sustain a population. Unless you grow some weed…sell it …then buy some real food. Maybe we should be looking into locust farming.

  7. you need to buy expensive lands to grow plants for food isn’t ?
    this technique is just amazing and i myselft applying it at home gardening

  8. Grown in a hydroponic system, what is a microscopic indicator for plant growth, or microscopic indicators for plants in general? For example the stomatal density (seen through a microscope) in a plant tells you whether there is more/less transpiration occurring.

  9. Hydroponics is really great and innovative idea of doing farming. The initial cost of setup is pretty high but it gives great benefit on long run. Hydroponics also helps in efficient use of water adding to its conservation.

  10. Hi there to everybody, it’s my first go to see of this web site; this weblog consists of awesome and in fact good stuff for visitors. Hurrah, that’s what I was exploring for, what stuff! Existing here at this blog, thanks admin of this web site. You can also visit related information and knowledge.

  11. Really very happy to say, your post is very interesting to read. I never stop myself to say something about it. You’re doing a great job. Keep it up.

  12. Nice information on hydroponic, i was using this system for more than 20 years up to now, even with these pandemic situation I was able to manage all my crops Tomatoes ,peppers and salads in a much better way to meet the demand whole year. hope some more articles like this.

  13. Really very happy to say, your post is very interesting to read. I never stop myself to say something about it. You’re doing a great job. Keep it up.

  14. Hi Valentina, thanks for sharing this excellent article. I believe that even if hydroponic technology never replaces conventional agriculture, in certain countries that have hostile soils for traditional cultivation they will be able to adopt this technology on a large scale.

    My family has implemented a hydroponic system for food production in a medium sized yard, it has been enough to produce food all year round and I use organic food in my recipes

  15. indeed hydroponics are a great usage of my nutrient filled urine. This season we grew urine lettuce with the system and it came out wonderful. just a little salty

  16. I generally searching Hydroponic kind of article and I found your article which is related to my interest. Genuinely it is good and instructive information. Thankful to you for sharing an article like this.

  17. Extremely useful information which you have shared here. This is a great way to enhance knowledge for us, and also helpful for us. Thankful to you for sharing an article like this.

  18. I like thisThis is a great way to enhance knowledge for us, and also helpful for us. Thankful to you for sharing an article like this.

  19. I got some unique and valuable information from your article. Thankful to you for sharing this article here.

  20. I got some unique and valuable information from your article. Thankful to you for sharing this article here.

  21. It’s good that you point out that hydroponic gardening allows you to grow food at any time of the year. Thank You

  22. I got some unique and valuable information from your article.
    Thankful to you for sharing an article like this.

  23. I believe that, commercially, the drip hydroponic system is the most popular. It’s also well-matched to vertical farming. However, for amateur household growers, I recommend starting off with a DWC (deep water culture) hydroponic system because it doesn’t require a big investment, there’s no need for a water pump, just an air pump suffices, and it’s very easy to build. It’s also a versatile system, where amateur growers can link together 5-gallon plastic buckets if they want a bigger yield from a crop. Valentina, thank you for such an extensive history on hydroponics, it was wonderful to read! I truly think that it has the potential to improve all our lives and I totally hope that more community centers will adopt it.

  24. I want to express my thanks to this writer for rescuing me from this particular circumstance. Just after scouting through the world wide web and seeing methods which are not pleasant, I believed my entire life was gone.

  25. Very informative content. Good researched. Thank you!
    I didn’t know that all Hydroponics built on found 16 Nutritions for growing plants.

    Thank you,
    Eva Green | Hydroponics Academy

  26. Amazing topic. I am exploring about hydroponic farming and lended in this article. I want to start hydroponic farming , which will not only suffice the food requirement of my area but provide a sustainable method for its production.Just a concern that in most of the videos of hydroponic farming, they are using plastic container to grow the plant. I would like to know , I’d there any other material we can use to grow plants.

  27. The article discusses hydroponics, a method of growing plants without soil, and its potential to revolutionize agriculture. It describes the basic principles of hydroponics and the advantages of this method over traditional soil-based farming, such as increased efficiency, reduced water usage, and faster growth rates. The article also provides examples of different types of hydroponic systems and their applications in different environments, such as urban farming and space exploration. Furthermore, the article discusses some of the challenges associated with hydroponics, such as the need for specialized equipment and expertise, and the importance of nutrient management. Overall, the article provides a good overview of the potential of hydroponics to transform agriculture and increase food production in a sustainable way.

Leave a Reply

Your email address will not be published. Required fields are marked *