HYDRO = water, PONOS = labour
Hydroponics is the art and science of growing plants in a solution of water and nutrients in which the roots are supported by a means other than soil. This technique may be used from small domestic crops to large commercial farms.
In this type of cultivation, water carries nutrients, an ideal solution of macro- and microelements that is essential to meet all the plants’ needs. Whatever the environment (soil or water) in which the plants grow, they absorb the nutrients in the form of ions dissolved in oxygen and, as for the water, whenever the nutrients and oxygen are absorbed, they have to be replenished. This is the principle of Hydroponics. It is, in short, a soilless cultivation method that stimulates plant growth while controlling the amounts of water, dissolved minerals and oxygen. Hydroponics may be used to grow the most varied types of plants,, vegetables, flowers, shrubs, herbs, and so on.
For good results, it is necessary to take several factors into account, such as the very genetic trait of the plant concerned, as it may be difficult to realize whether the plant is responding well to the culture medium and its conditions or what is embedded in its DNA. It must also be noted that Hydroponics focuses on plant feeding, and is the consequent result of a balanced diet rather than the manipulation of a plant’s metabolism.
The environment, just like temperature and relative humidity, have a direct effect on plant growth. Plants love fresh air. Their vital processes, such as photosynthesis and transpiration, are dependent on adequate levels of temperature, humidity and air circulation. Depending on the plant species, those levels vary between 15º and 30º degrees Celsius (50º – 86º F) and the relative humidity between 40% and 100%.
Another factor to consider is light, as it affects plant growth and provides the energy used for photosynthesis. The choice of the place of cultivation must take seasonal variations into account, as well as the shadow caused by buildings or trees and sun exposure. If using artificial light, it must have a broad spectrum and intensity in order to meet all the plant’s needs. Different plants have different growth stages and require different light spectra and intensity.
Logically, the quality of water also affects the health and vitality of the plant. For instance, tap water may contain too much chlorine and present a very high pH level. A set of several factors may cause a reaction in the nutrient solution, resulting in the fusion of various essential elements and making them unavailable to plants. Therefore, the control of and tests on water are important to make some adjustments, if necessary.
As the cultivation in soil, Hydroponics is not free from pests, whether fungi, viruses, insects and arachnids. Cleaning may prevent many of these problems. Keeping the surfaces/gardening tools sterile hinders the spread of viruses and bacteria. Excessive temperature and relative humidity are also favorable to pests/viruses. By increasing air circulation, we reduce condensation and prevent this problem. Basically, a good maintenance and cleaning are a fine start in preventing diseases.
Advantages and Disadvantages
Higher yield per area. As it waives the use of soil, hydroponics can be verticalized. In Japan, for instance, there are hydroponic crops grown underground, in old subway stations;
Increased plant productivity. As the roots receive and have available all the nutrients they need full-time, they do not waste much energy looking for them in the soil, and so the plant can focus on foliage and fruit, and thus the whole crop grows healthy;
Higher product quality. As it can grow indoors, vegetables are less susceptible to pests and diseases, and as the plant itself is healthier, it is more resistant and requires less fertilizers;
It allows harvests throughout the year by resorting to greenhouses;
More efficiency and economy in the use of water and fertilizers;
Shorter vegetation and fructification cycles due to better environmental control. Lettuce, for instance, takes 60 – 65 days to be harvested in conventional cultivation, while in Hydroponics this period is reduced to 35 – 40 days;
Control over nutrition;
Dependence on electricity or alternative power systems (in the case of active systems). If there is a power shortage and the producer does not have a generator, then there is the risk of losing the entire production;
Higher initial investment in equipment;
Requires knowledge of technology and continuous monitoring (in the case of commercial farms);
Ease of spread of pathogens in the system by its own circulating nutrient solution.