Stock solutions are essential component of any hydroponic farm. Imagine a system, 5,000 m² in size growing tomatoes. The estimated number of plants would be 15,000. On average tomato plants consume 1.5 – 2 L of water per day. The system would require at least 30,000 L water per day. If a grower has one 10,000 litre nutrient tank, he would have to mix and refill the tank three times a day. That is a lost of time wasted by labour mixing and refilling. However, if the grower could install three 1,000 L tanks, concentrate the solutions in these tanks by 100 times, each tank would hold an equivalent of 100,000 litres of nutrient solution. The grower would have to mix every 3rd to 4th day instead of three times per day, a considerable savings in time.
Stock solutions are nutrient solutions that are concentrated many times in order to save time in mixing and reduce the size of tanks. Stock solutions are used in situations as described above and when fertilizer proportioner or injector systems are used. The fertilizer injector can be installed for a closed or open hydroponic system. The type of system is irrelevant, it is the computer system or type of fertilizer injector layout that differs but they provide the same function.
Many growers that start of with a small hydroponic farm don’t use stock solutions. However, as soon as the work load increases, stock solutions become a necessity and some system must be implemented. Prior planning and a good understanding of the various types of stock solutions is important to help you make the right decision.