What is EC and PPM?
The EC is for many people just as the pH values – a twilight zone, although it is not that complicated. EC stands for Electro Conductivity and is measured in ms; conductivity of electricity in a liquid occurs through conductive particles. The nutrients (elements) that are necessary for your “favourite plants” become negatively and positively charged particles as soon as they dissolve. The more of these particles present, the better electricity is conducted, the higher the EC. Therefore the EC is a measure of the amount of nutrient present in a solution. Reiziger nutrients are vital to the plant and because these nutrients are directly available, you must proceed very carefully.
A too high EC will produce a too high osmotic pressure around the roots. Osmosis? A liquid moves, according to physics, in the direction of the strongest solution. Is the solution outside the plant stronger than inside, then the plant empties itself (simply said). This emptying of the plant can be noticed in practice as a so called burning of the leaves. (When leaf blades curl down they are trying to conserve water).
In general we advise that the EC with rockwool lies between 1.6ms and 2.5ms. (Of course we talk about the EC in the slab). When making a nutrient solution always adjust the EC first and only then the pH value. This is because Reiziger nutrients are very acidic and the addition of nutrient has a direct influence on the pH .
Reiziger nutrients are sold in concentrated form and consist of different parts. These parts, A and B, are packaged in separate jerrycans. This is because the separate parts work negatively together in their concentrated forms. Therefore always ensure that when making a nutrient solution these concentrated part (A and B) never come in contact with each other. Mix part A with the water and only then add part B. If the packaging advises 1:250 (4ml/L/qt), then for example begin with a solution of 1:300 (3.3ml/L/qt), then after stirring thoroughly measure the EC and if necessary add some more to reach the correct value. Let the nutrient solution stand for approximately 2 hours (to work in) and then adjust the pH value.
Questions like how much feeding solution does my plant require in week 3 and how much in week 6 are impossible to answer. This is related to the size of the plant, the amount of leaves, height of the lamps, relative humidity, temperature, root development, ventilation per m/hour. The only good answer to this question is that you must learn to see how your plant feels and learn to feel the weight of the rockwool slab (to determine if it is wet enough). The EC you must use also depends on the requirements of the sort. When your plant looks healthy, fresh and green you are doing the right thing.