WHAT IS HYDROPONICS? Hydroponics is a subset of hydroculture, the method of growing plants without soil, using mineral nutrient solutions in a water solvent. Terrestrial plants may be grown with only their roots exposed to the mineral solution, or the roots may be supported by an inert medium, such as perlite or gravel. The method can be implemented in places where the soil type is not ideal for the desired crop. Hydroponics uses 80 to 90% less water and nutrient than the same crop grown in soil. It uses no herbicides and generally resorts to integrated pest management (IPM) to insure the result is high quality, nutritious and safe food. Hydroponics can be installed anywhere and everywhere – in the countryside, crowded cities, poor regions and extreme conditions – to get food closer to customers, while reducing the carbon print of shipping. The technique can be used in roof top farming and therefore is very useful in areas with limited space such as urban areas. Hydroponic systems can be designed to fit all sizes of space and convert them into gardens. Considering that hydroponics will give as much as 30% more yield than soil, the smallest growing area becomes a productive hydroponic garden.
WHY GO THE HYDROPONIC ROUTE? Hydroponic systems are fast becoming a popular choice for many gardeners and farmers around the world, due to its more sustainable approach to resource usage than the usual growing methods. Here are some of the many reasons why hydroponics is taking over as a personal and commercial choice for growing all sorts of crops: The simplified hydroponic technique is easy to understand and does not require any prior knowledge to achieve concrete results. By providing constant and readily available nutrition, hydroponics allows plants to grow up to 50% faster than they would in soil. Also, fresh produce can be harvested from a hydroponic garden throughout the year.
Great for both the environment and the grown product, hydroponic gardening virtually eliminates the need for herbicides and pesticides compared to traditional soil gardening.
Any water that is used in hydroponic gardening stays in the system and can be reused, reducing the constant need for a fresh water supply, so it is advantageous in drought prone areas or deserts.
Arable land is often in short supply and gardening space continues to decrease. A great option when you lack yard space or have a tiny balcony, hydroponics also lends itself really well to indoor gardening.
There is no crop limitation due to soil type, eroded or diseased soils and no nutrition waste due to water run-off, which in turn can lead to eutrophication. There is also less frequent occurrence of diseases because of the absence of soil which is a bacteria growth media.
Higher and more stable yields, because hydroponically grown plants do not have to expend energy finding nutrients in the soil or competing for food and water, since the adequate nutrients are delivered straight to the roots.
Due to container mobility, hydroponics enables the farmer to grow crops near the area of use, thus reducing transportation costs and carbon footprint.
Labour intensive work such as tilling, cultivating, fumigation and watering is not required for hydroponic farming, and as automated systems develop using pumps or even computers, traditional labour costs will decrease dramatically.
WHAT ARE THE CHALLENGES? Although the use of advanced hydroponics is cheaper in the long run, the initial start up cost can be rather high as it is expensive to procure the equipment required.
The hydroponic conditions, in particular the presence of fertiliser and the high humidity, create an environment that stimulates salmonella growth.
The process also requires the use of uncontaminated water, which may pose problems if supply is unreliable.
FOUR HYDROPONIC TECHNIQUES Nutrient Film works best with plants that have a long root system. The system consists of a sloped channel that allows the nutrient water to be continuously pumped and circulating in the channel. Plants are suspended above with their roots dangling into the solution. This technique requires constant maintenance, as overgrown roots can block the channel and disrupt the whole process. It also requires a constant flow of nutrient solution or else the plant will dry out, so the pumps must be very effective. For this reason this method is not advisable for home gardening or developing countries. Dynamic Root Floating Technique (DRFT) is a non-circulatory method implemented using simple pumps, and therefore advisable for developing countries. The pump is not continuously in use, but is switched on and off periodically. The bottom of the roots dangle in the nutrient solution and specialize in nutrient uptake (technically named ‘nutriroots’) whilst the upper part or ‘aeroroots’ are not in solution and are responsible for oxygen intake. DRFT keeps the temperature constant and so is desirable for hydroponic farming in tropical and subtropical climates such as the Caribbean. Water Culture Technique requires the roots to dangle freely in the solution, although the problem of root aeration often arises and therefore an air pump is used to supply oxygen. The roots must not be exposed to light as it gives rise to nutrient-consuming algae. This technique is ideal for fast growing plants such as lettuce.
IMPLEMENTATION IN DEVELOPING COUNTRIES Advanced hydroponic systems can be intensive and expensive. But simplified hydroponic growing is much simpler and cheaper with low operational and maintenance costs. Although yields from such systems are lower in comparison to advanced hydroponics, the yield still outweighs regular farming yields. In addition, cheap and easily available materials such as fish aquarium tanks, ceramic pots and aluminum cans can be used. It is also useful in urban areas where there is limited land for cultivation. Simplified hydroponics was developed in the early 1980’s in Colombia. These projects were a success as on average a single garden made a profit of $90 in two to three months with the initial investment being $355.
Since 1984, projects have been implemented in 12 Latin American and African countries, mostly funded by the UNDP and the UN FAO.