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What Are Hydroponic Systems and How Do They Work?

Hydroponics is the art of gardening without soil. Hydroponics is a Latin word meaning “working water.” In the absence of soil, water goes to work providing nutrients, hydration, and oxygen to plant life. From watermelons to orchids, plants flourish under the careful regimen of hydroponics. Using minimal space, 90% less water than traditional agriculture, and ingenious design, hydroponic gardens grow beautiful fruits and flowers in half the time.


Though the technology sounds cutting-edge, the history of hydroponics dates back to the famed Hanging Gardens of Babylon, one of the Seven Wonders of the Ancient World. The Euphrates River was diverted into channels that cascaded down the lavish garden walls. In the 13th century, Marco Polo wrote of witnessing floating gardens in China. However, hydroponics is far from merely an innovation of the ancient ages. In the 1990s, NASA grew aeroponic bean seedlings in zero gravity aboard a space station, opening up the possibility of sustainable agriculture in space. Hydroponics continues to be a timeless and dynamic method of water conservation and crop production. 

What is hydroponics? 

Hydroponics is the cultivation of plants without using soil. Hydroponic flowers, herbs, and vegetables are planted in inert growing media and supplied with nutrient-rich solutions, oxygen, and water. This system fosters rapid growth, stronger yields, and superior quality. When a plant is grown in soil, its roots are perpetually searching for the necessary nutrition to support the plant. If a plant’s root system is exposed directly to water and nutrition, the plant does not have to exert any energy in sustaining itself. The energy the roots would have expended acquiring food and water can be redirected into the plant’s maturation. As a result, leaf growth flourishes as does the blooming of fruits and flowers.   

Plants sustain themselves by a process called photosynthesis. Plants capture sunlight with chlorophyll (a green pigment present in their leaves). They use the light’s energy to split water molecules they’ve absorbed via their root system. The hydrogen molecules combine with carbon dioxide to produce carbohydrates, which plants use to nourish themselves. Oxygen is then released into the atmosphere, a crucial factor in preserving our planet's habitability. Plants do not need soil to photosynthesize. They need the soil to supply them with water and nutrients. When nutrients are dissolved in water they can be applied directly to the plant’s root system by flooding, misting, or immersion. Hydroponic innovations have proven direct exposure to nutrient-filled water can be a more effective and versatile method of growth than traditional irrigation. 

How does hydroponics work? 

Hydroponic systems work by allowing minute control over environmental conditions like temperature and pH balance and maximized exposure to nutrients and water. Hydroponics operates under a very simple principle: provide plants exactly what they need when they need it. Hydroponics administer nutrient solutions tailored to the needs of the particular plant being grown. They allow you to control exactly how much light the plants receive and for how long. pH levels can be monitored and adjusted. In a highly customized and controlled environment, plant growth accelerates.   

By controlling the environment of the plant, many risk factors are reduced. Plants grown in gardens and fields are introduced to a host of variables that negatively impact their health and growth. Fungus in the soil can spread diseases to plants. Wildlife like rabbits can plunder ripening vegetables from your garden. Pests like locusts can descend on crops and obliterate them in an afternoon. Hydroponic systems end the unpredictability of growing plants outdoors and in the earth. Without the mechanical resistance of the soil, seedlings can mature much faster. By eliminating pesticides, hydroponics produce much healthier and high-quality fruits and vegetables. Without obstacles, plants are free to grow vigorously and rapidly. 

What are the components of a hydroponic system? 

To maintain a flourishing hydroponic system, you will need to become acquainted with a few components that make hydroponics run efficiently. 

Growing media

Hydroponic plants are often grown in inert media that support the plant’s weight and anchor its root structure. Growing media is the substitute for soil, however, it does not provide any independent nutrition to the plant. Instead, this porous media retains moisture and nutrients from the nutrient solution which it then delivers to the plant. Many growing media are also pH-neutral, so they will not upset the balance of your nutrient solution. There are a host of different media to choose from, and the specific plant and hydroponic system will dictate which media best suits your endeavor. Hydroponic growing media is widely available both online and at local nurseries and gardening stores.  

Air stones and air pumps

Plants that are submerged in water can quickly drown if the water is not sufficiently aerated. Air stones disperse tiny bubbles of dissolved oxygen throughout your nutrient solution reservoir. These bubbles also help evenly distribute the dissolved nutrients in the solution. Air stones do not generate oxygen on their own. They need to be attached to an external air pump via opaque food grade plastic tubing (the opacity will prevent algae growth from setting in). Air stones and air pumps are popular aquarium components and can be purchased easily at pet stores. 

Net pots 

Net pots are mesh planters that hold hydroponic plants. The latticed material allows roots to grow out of the sides and bottom of the pot, giving greater exposure to oxygen and nutrients. Net pots also provide superior drainage compared to traditional clay or plastic pots.

Nutrient film technique systems NFT

Nutrient film technique (NFT) systems suspend plants above a stream of continuously flowing nutrient solution that washes over the ends of the plant’s root systems. The channels holding the plants are tilted, allowing water to run down the length of the grow tray before draining into the reservoir below. The water in the reservoir is then aerated via air stone. A submersible pump then pumps the nutrient-rich water out of the reservoir and back to the top of the channel. The nutrient film technique is a recirculating hydroponic system. 

Unlike with deep water culture hydroponics, the roots of the plants in an NFT system are not immersed in water. Instead, the stream (or “film”) only flows over the ends of their roots. The roots’ tips will wick the moisture up into the plant,  while the exposed root system is given plenty of access to oxygen. The bottoms of the channels are grooved, so the shallow film can pass over the root tips with ease. This also prevents water from pooling or damming up against the root systems. 

Even though nutrient film technique systems are constantly recycling water, it is wise to drain the reservoir and replenish the nutrient solution every week or so. This ensures your plants are being delivered ample nutrition. NFT channels must be angled at a gradual slope. If it’s too steep, the water will rush down the channel without properly nourishing the plants. If too much water is being pumped through the channel, the system will overflow and the plants can drown. NFT hydroponics are popular commercial systems, as they can support several plants per channel and can easily be mass-produced. Nutrient film technique systems are best suited for lightweight plants, like mustard greens, kale, lettuce, spinach as well as fruits like strawberries. Heavier fruiting plants like tomatoes and cucumbers will require trellises to support the excess weight. 

Why should I use RO water for hydroponics?

Reverse osmosis water allows you to start with a blank slate and add precise levels of nutrients, promoters, and pH adjusters to your water. From this neutral base you can construct the ideal nutrient solution. For example, if you live in an area with hard water, your water will already contain high levels of calcium. Many hydroponic nutrient blends contain calcium, as it does encourage plant growth. However, adding a calcium-rich solution to hard water will result in nutrient imbalance. It is also much harder to measure nutrient levels in water with high levels of TDS. Most manufacturer's instructions for nutrient solutions are based on RO water. So, if you are trying to bring the water to 800ppm of nutrients, and the water already exists at 200ppm of TDS, you will have to approximate. The results will inevitably be inaccurate. Reverse osmosis water is also lower in pH. Plants prefer acidic water, and using RO water to hydrate your crops will lessen the amount of pH regulation incumbent on you as a grower.     

Controlling the nutrient balance and pH level of your water is an integral component to your hydroponics’ success. If your plants are not receiving proper nutrition, it doesn’t matter how well your hydroponics system is running. A reverse osmosis system ensures that your plants are only absorbing proper nutrients dissolved in water of the highest purity. 



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