With the nutrient layer systems (NFT), a method for cultivating small plants with a short cycle, the drip irrigation technique (Drip systems) is for greenhouse farms and crop production on an industrial scale. This is the most popular type of hydroponic system. The nutrient solution enters the plant in doses, drop by drop, or in small streams.
The invention of mineral wool, as a new substrate for hydroponics, has served the rapid development of drip irrigation systems. Mineral wool is a volcanic rock, expanded at high temperature and rolled into the fiber. This fiber is then molded into slabs or cubes of any size. Then slabs or cubes of mineral wool covered with a sheet of plastic. Consider the classic scheme of the production site for growing tomatoes.
Long rows of mineral wool slabs are laid on plastic wrap. They are slightly raised, and an excess nutrient solution flows to the side of the tray. Along each row ? the main line ? a polyethylene pipe delivers the nutrient solution. Plants are in mineral wool cubes, and when their roots start appearing from the bottom of the cube, they are placed at regular intervals on the plates.
From the supply line, secondary thin plastic spaghetti nozzles irrigate each plant separately. At the end of the nozzle, a small plastic pin secures the nozzles at the top of each cube and slowly releases drops (hence the name), irrigating the cube. The rate of release of the droplets is adjustable. The timer controls the circulation and activated at different times during the day depending on the needs of the plant, due to weather conditions and other factors. Excess nutrient solution, which is 25?30% of the total volume, does not return but is released into the environment, and this is very distressing. The reason for this waste is that you need to flush out salt from the plates and ensure that the last plants in each row receive enough solution. So why not return the solution and not reuse it? Because it is cheaper! In the greenhouse industry, it is believed that when the nutrient solution circulates in a closed circuit, pathogens also circulate with it. They will quickly get to the whole harvest. This means that for reuse you need to somehow sterilize the nutrient solution, which is very problematic. This theory is questionable. Specialists who grow hundreds of plants in closed loops do not experience any problems. Several plants always die, but they are scattered in various places. These are the weakest plants, and this happens with them and in open systems. Insects and the wind may cause diseases and always find a loophole for themselves. Ultimately, if the plants are healthy, their defense mechanisms and immune system will stop this invasion ? the dynamics are the same as in humans and all living things. Another reason for not using the solution again is the fact that not all salts are absorbed at the same rate. Before recycling, analyze the solution and make ion balanced. Thus, the reuse of the same solution enters into a pretty penny, it is cheaper to drain it into the nearest reservoir.
However, according to the new legislation on waste recycling, wastewater treatment is obligatory. Slowly and not without coercion, the greenhouse industry begins to acquire environmental awareness. New substrates introduced: first, glass wool (not very different from mineral wool), then coconut fiber plates and a decomposable substrate, opening up the prospect of more environmentally friendly use of drip technology.
Surprisingly, this type of system appeared in variants adapted to indoor cultivation. One of the reasons is considerable cheapness. However, the fact that after each growing cycle it is necessary to replace the substrate, makes it expensive to operate. Only rectangular plastic trays needed, in which plates of mineral wool, glass wool, coconut fiber, etc. placed, a very small pump, a cheap supply line with secondary spaghetti hoses. An excess nutrient solution, which is often simply discarded, is collected in a tank located below. The minimum dimensions of such a system: 30?55 cm.
Drip systems are reliable and easy to operate and best for beginners. To some extent, the environment protects the roots from sudden changes in temperature and humidity, but in general ? from operator errors. For these systems, the irrigation cycle is vital: too much water ? the roots rot from oxygen starvation; little water ? salts crystallize on a cube and interfere with the absorption of the roots. From the point of view of oxygenation, this is far from ideal, since the substrates used to retain a large amount of water. In cold climates, this water cannot be absorbed quickly enough for fresh air to take its place. As a result, sinuses of root rot are formed, which are often found with drip irrigation. The interval between the two irrigation cycles, when conditions in the root zone are ideal, is very short: the rest of the time, the substrate is either over-moistened or overdried.
If you want to experiment with hydroponics without spending money, then you can start with drip irrigation, but you need to use a plate of coconut fiber, and not mineral wool. And if you do not reuse the nutrient, you can at least water it with home or yard plants. During re-usage, there is an insignificant amount of substrate. Indoor cultivation is a thriving industry involving literally millions of people all over the world and in the most unexpected places. If you collect all the waste, you get an impressive mass, and then there will be no time for jokes! Of course, the larger the area of seedlings, the greater your impact. Many conduct their first hydroponic experiments using plates and drip irrigation because this substrate is closest to the soil and does not look as scary as bare roots. They usually get good results, but over time, when they become more self-confident, they often switch to another method described above.
Free Expert Advice for Growing Vegetables and Fruits Hydroponically - Questions and Answers