Centuries ago, it would have been difficult to imagine that we could grow crops without soil. Rich soil has traditionally been an essential requirement for growing plants, but technological advancements in agriculture are changing. Hydroponic systems are challenging traditional soil gardening and may well be the plant growing system of the future.
Hydroponics is a technique used for growing plants without soil. Hydroponic systems cultivate plants in nutrient-enriched water with a supply of air and light needed for photosynthesis. We call this particular technique that uses only water, nutrients, and light, aeroponics. In some situations, a bit of gravel, peat, perlite, rock wool, or sand is used to aerate and provide support for the root system. We refer to these materials as mediums. In such situations, they pump the nutrient solution through the tubes or tanks periodically.
We also refer to hydroponics as aquaculture, nutriculture, tank farming, or soilless culture.
Commercial hydroponics growers adopted the laboratory practice of growing plants in water and fertilizer solutions for scientific studies. They create the nutrient solution with nitrogen, potassium, and phosphorus. Other elements like sulfur, calcium, and magnesium may be added.
A wide variety of plants are suitable for hydroponics growing. We can grow vegetables, herbs, fruits, and flowers.
There are different systems farmers employ in hydroponics. According to experts, we can group these systems into two major categories2. They are solution culture types and medium culture types. We examine each category and some of the techniques under it below.
Aeroponics: in this system, they keep plant roots in an environment where they are regularly supplied with a mist of nutrient solution and air. Aeroponics uses 65% less water than other hydroponics techniques. It also receives more oxygen and encourages faster crop growth. It is not suitable for every kind of plant and has a high risk of exposure to root disease pathogens.
Nutrient film technique: this is a popularly used hydroponic system. The nutrient film technique is designed to allow a continuous shallow stream of nutrient solution to flow past the bare roots in water-tight channels. The advantages of this system are that it readily supplies adequate water, oxygen, and nutrients to the plants. The challenges farmers face with this technique are the risk of flooding and dependence on a constant power supply.
Ebb and flow: here, they do the growing by using a medium through which farmers pump the nutrient solution. They allow the flow to flood the area and then drain. The solution drains into a reservoir which they reuse almost immediately. This system is the most popular due to its low costs and maintenance. It is most suitable for potted plants and plug production.
Deep Water Culture: this system is the most simple-to-operate hydroponic system. They simply suspend the plants in a solution of oxygen and nutrients. It is one of the easiest to maintain and expand. This technique is suitable for growing vegetables.
Prevailing traditional agricultural methods are not sustainable. Heavy consumption of pesticides, wastewater, emissions, deforestation, and ecosystem disruption are some of its issues. Climate change, economic crises, and pressure on the environment put the food chain stability at risk.
Urban agricultural practices like hydroponics build up the agricultural potential of cities. At the same time, delivering positive environmental benefits. Since farmers can control the nutrient supply to the plants via hydroponics, they can grow crops in or out of season. They need to consider other factors like exposure to sunlight and temperature, yet they can manage those using farming methods that enable them to control their farm environment.
According to research on the environmental benefits of hydroponic growing in urban Europe, carbon-neutral hydroponic food production outperforms the two conventional types of agriculture1.
The hydroponic system uses ten times less water than traditional soil-based farming. This is because it is unlike field crop watering, where water has to be sprayed till the soil absorbs it. In hydroponics, the systems deliver nutrients solutions directly to plant roots. When they pump it through a medium, absorption is not necessary. The water which contains nutrients is recaptured and reused, unlike in traditional farming, where water is allowed to run off into the environment. This eliminates the need to source water resources often.
In places where water scarcity is a problem, hydroponic systems can radically improve water consumption in farming.
Hydroponic systems eliminate the problem of weed growth which, in turn, means zero herbicides use. Using herbicides in traditional farming contributes to air pollution and soil contamination. Also, because the plants are not in the soil, there is no chance of chemical fertilizer contamination.
The intensive use of pesticides is one of the problems of traditional agriculture. Thanks to the controlled environment, pest attacks are not an issue in hydroponics. This means that there is minimal use of pesticides, if at all.
Farmers can reuse the nutrient solution in hydroponics indefinitely, although the nutrients themselves require replacing as depleted. They collect the solution as it drips from the channels into a nutrient reservoir. Also, farmers can get nutrients from various sources. One technique, aquaponics, uses fish excrement as a nutrient source.
Hydroponic growing can occur all year long as seasonality does not limit it like traditional soil-based farming. This means that seasonal food scarcity due to snowfall or no rains can be reduced or eliminated. It presents an opportunity to improve the food supply.
The hydroponic growing system produces a greater yield of fruits and vegetables compared to traditional farming. This is because elements that determine plant health and yield are better monitored and controlled. These elements include light, water, nutrients, and pH.
Also, because the plants are more densely packed, a hydroponic farm will yield much more than a field plantation of the same size. One other benefit of hydroponics is that it has a faster plant growth rate. Also, hydroponics is practicable almost anywhere in the world.
Hydroponics does not consume large expanses of land like traditional farming. With hydroponic growing, we can produce food locally without occupying agricultural land. This makes it an excellent option for land conservation without harming the food supply. We can do it indoors and outdoors, so it is possible to operate thriving hydroponics gardens in rural areas and built-up urban settlements.
Hydroponics also helps conserve space as they usually arrange the tubes vertically, allowing farmers to use space above the ground. This is possible by anchoring the tubes to frames or suspenders.
In many ways, hydroponics can help to reduce the agricultural sector’s contribution to global warming. It is not as carbon-intensive as traditional soil-based farming and encourages local food production and supply. Large-scale hydroponic systems operating in urban areas bring food supply closer to consumers. It cuts back on transport emissions generated along the supply chain.
The hydroponics system is not free of challenges. Farmers have to measure and control the electrical conductivity, pH, temperature, and dissolved oxygen. The margin for error in maintaining the right balance of all these elements is tiny. One slight mistake may affect the system severely. These challenges, however, do not reduce the environmental benefits of the hydroponic system in any way.
Diseases: the benefits of hydroponics do not include immunity to diseases. Pathogens can quickly spread because the water is recirculated. Therefore, the hydroponic system requires close monitoring. Not just to monitor the level of nutrients but also to ensure that the plants are protected from diseases.
Energy use: depending on the environment, indoor hydroponic gardens may need an artificial light source. Also, most hydroponic techniques require an electric pump to keep the nutrients and water flowing. These consume energy. According to research, fossil fuel use decreases the benefits of hydroponic production. Therefore, it is important to ensure that the energy source is clean and sustainable.
Food safety: some rules may guide growing plants in hydroponic systems in your locality. These rules may dwell on safety practices for commercialized hydroponic gardens. You must find out what regulations exist in your area and how they affect your hydroponic gardening endeavors.
You can apply hydroponics to home gardening successfully. It is an excellent option for people who do not have space for traditional gardening. You will need a number of things, including nutrient solutions, which can be bought at a store or made at home.
If you are growing plants hydroponically indoors, it helps to have an artificial light source to stimulate healthy plant development. Also, ensure that the space has excellent air circulation.
It is best to use vertical hydroponic systems to grow your vegetables and herbs.
Adopting hydroponics is one of the ways the world can move towards sustainable agriculture. It is also a valuable tool in combating food scarcity as it allows plants to be grown in and out of season.
Diana R. et al. (2018) Environmental impacts of urban hydroponics in Europe: a case study of Lyon.
Petrus Langenhoven (2016) Opportunities in hydroponics. Purdue University.