Have you ever wondered why the vegetables sold in supermarkets appear largely identical in terms of their sizes and taste? Hydroponics is a technique of farming food crops using mineral nutrient solutions in water, without the need for traditional soil-based growing. Over the years, hydroponics farming has been refined to allow food crops to grow at an efficient rate to meet the increasing demand for human consumption. Food crops grown are high on food quality standards as they are free of pests, soil diseases or harmful chemicals. Hydroponics vegetables appear more uniform with considerably higher yield than conventionally soil-grown crops as they are exposed to uniform, controlled growth conditions. With the aim of producing a sustainable food source for Singapore’s growing population, six different hydroponics systems have been identified to be able to support farming a variety of food crops, depending on their needs for healthy growth.
Figure 1. Commercially-viable setup of Greenology Vertiponix™ system that utilizes Nutrient Film Technique.
Greenology Vertiponix™ (Figure 1) adopts the Nutrient Film Technique (NFT) of growing plants in a thin layer of nutrient solution (Figure 2). This technique of hydroponics is most suitable for plants with smaller roots, including most fast-growing herbs and leafy vegetables. Because the crops are grown under Greenology Grow Lights™ that are used to provide optimal photosynthetic flux for vegetable growth, a faster harvest of crops is made possible without compromise in food quality. Using power generated from solar panels, this closed system reticulates water and nutrients with minimal water wastage to ensure low carbon footprint. Given the space-constraint that Singapore faces, growing tubes are stacked vertically on a lightweight aluminium rack to increase food production per square meter. Greenology Vertiponix™ system is scalable for commercial, schools and even home settings, making it an ideal solution for small-scale urban farming.
Figure 2. Basic illustration of Nutrient Film Technique as used by Greenology Vertiponix™.
Hydroculture or water culture, as implied by its name, is a system where plants are grown by soaking the roots in water. Would this result in over-watering and subsequently root rot? It has been found that when water is aerated sufficiently and kept at the right temperature, plants will thrive because of the uptake of oxygenated water from the roots. This system provides a continuous supply of water for food crops by suspending plants in a pool of nutrient solution, allowing the plants to take in as much water as it needs (Figure 3). An air stone is also placed in the reservoir tank to incorporate oxygen into the nutrient solution. With this large supply of water, the system allows crops that require large amount of water to grow well. Examples of these plants include tomatoes or even pumpkins!
Figure 3. A standard setup of Hydroculture with air stone to incorporate oxygen into nutrient solution.
The Ebb and Flow hydroponics system (Figure 4) supports a larger variety of plants. Water in this system is allowed to flow freely, periodically supplying the necessary nutrients for plant growth. The open bed space permits the water to permeate the entire grow tray and reach the plants. As such, larger plants are able to grow in this setup as there is no constraint on pot size. Crops with roots that require more aeration do well in this system. Chilli varieties do best in the ebb and flow system. Also, the use of heavy media like gravel and pebbles provide adequate support for these larger plants.
Figure 4. A typical Ebb and Flow hydroponics setup with periodic drainage of nutrient solution.
After covering three of the six common hydroponics systems, you might have already discerned the similarities between them. All three systems make use of nutrient solution for crop growth, without the addition of any chemical pesticides. As no soil is used for crop growth in hydroponics, hydroponic systems are a cleaner and more suitable option especially for indoor urban farming. Compared to organically grown soil-based crops, hydroponic food crops are grown in a controlled, sterile environment that is pest-free, making the possibility of better food quality likely.
Figure 5. Lettuce grown using the Greenology Vertiponix™ system.