The word “hydroponic” comes from Latin and means “working water”. Simply stated, it is the art of growing plants without soil. The essential differences between hydroponics and field production are that hydroponics offers:

• No soil-borne diseases

• Better management of plant requirements

• Control of the growing environment

• A faster growing cycle (more overall production per season)

• More yield overall

• Better produce quality (fewer unmarketable grades).

The cost effectiveness of hydroponic production depends on the type of plants grown and the target market. Each hydroponic method is optimised for a specific type of produce. For example, leafy crops such as lettuce are extremely cost effective if grown with the nutrient film technique, as opposed to bag culture. It’s about choosing the right horse for the right course. On the other hands, tomatoes will be extremely expensive to grow with nutrient film, but perfectly suit bag culture. Of course, as with agriculture in general, growers earn less than buyers, while consumers pay the highest price. The advantage of hydroponics is in the increased yield. In fact, hydroponics may eventually be the saving grace of humankind. In the near future, it is expected that 90% of food produce will be produced hydroponically, including fruit. In some instances, this is already the case—figs, grapes and berries, for example. As a rough estimate, I would say that some 60-70% of South Africa’s vegetable output is currently produced hydroponically.

In terms of soil, irrigation and nutrition, it must be emphasised that hydroponics is a soil-less cultivating environment. This allows for a more precise and focalised irrigation plan. From a plant nutrition viewpoint, plants receive better nutrients, which manifests in higher nutritional values. However, the difference in nutritional value between hydroponics and soil cultivation varies depending on the types of plant and other conditions.

Hydroponic vegetables are fertilized in the same way as in field production, in that all plants use the same natural elements. There is only one type of calcium atom, for example. However, under soil production, it has to be broken down by bacterial activity in order to become available and recognisable by the plant roots. This means it takes time for the fertilizer to be processed from application to availability. Under hydroponics, one the other hand, nutrient elements are highly soluble and available in the right chemical configuration for recognition and uptake by the plant roots. This means that plants benefit from having the right elements constantly available, which boosts plant development. When it comes to diseases, there are ups and downs to hydroponics. For example, soil-borne diseases such as bacteria and fungus require a soil environment to sustain themselves: they need a balanced pH, constant moisture and the right temperature. Change one of these parameters and they won’t develop. Soil-borne diseases such as nematodes cannot migrate into hydroponic growing medium.

On the other hand, greenhouse disease control is a huge issue as the humidity and temperature of the greenhouse environment are perfectly conducive to promote airborne diseases. Consequently, it is essential to implement integrated pest management to avoid rapid infestation. Would-be hydroponics farmers should note that the capital investment requirements are high. Setting up is a one-off cost which is much higher per hectare than open field farming.

However, provided that other factors such as a secure market and appropriate infrastructure are taken care of, a hydroponics business will break even in a very short time. Thanks to the high yield and quality produce that hydroponics enables, the profitability trade-off is mostly 4:1. Basically, more produce grown at higher quality commands better prices. Although hydroponic production is said to be more capital, management and labour intensive than field production, this really depends on the type of crop. Potatoes are less resource intensive than tomatoes. Overall, though, hydroponics does require more knowledge and expertise than field production.

For hydroponics to succeed, producers need to have a supporting environment including modern quality infrastructure, plant material, fertigation, nutrients, accessories, expertise, and a ready market. Fortunately, these are all available in South Africa, which makes getting started an easy task. In Nigeria, by comparison, it is practically impossible to get started even on a small scale, as all the necessary elements have to be imported at high cost and expertise is lacking. If you put water to work with hydroponics and do all your homework, you can have a thriving business in a relatively short period of time.
Ben Safronovitz, hydroponic consultant