Hydro grains are made of pure and salt-free baked clay. They contain a very low concentration of elements. The quality of hydro grains is largely determined by the pH. In addition the concentrations of Sodium and Manganese are important.
Hydro grains are used for various growing methods, sometimes they are placed at the bottom of the flowerpot when growing on a substrate like soil. The hydro grains are used as an additional drainage, so drainage and the supply of oxygen from below are more effective. Sometimes hydro grains are mixed in the substrate, to make the growing medium airier. The roots can also branch off better.
A third method that is widely used, is growing the plants directly on hydro grains. This is often done in combination with an oxygen pump. This way the roots at the bottom of the pot are constantly immersed in water with liquid fertilizers mixed in, and the oxygen pump provides enough oxygen for the roots. This growing method is very successful. The hydro grains and the flowing water nutrient solution form a golden duo when it comes to a lavish supply of oxygen. The plants both get oxygen from the top (because the hydro grains allow so much air to pass through) and from below. The flowing water contains many times more oxygen than ordinary still water. Actually still water should be out of bounds anyway, because it turns acid easily and/or can cause any variety of diseases. As a grower we can notice that the plants appreciate the abundance of oxygen. The plants grow quickly and develop a highly branched root system, what should give them adequate footing to develop a sturdy stem and branches during the cycle. This will allow the plants to produce beautiful flower bunches during the flowering cycle. The great weight of hydro grains ensures that the plants have even more footing, enabling them to carry a proper weight of flower bunches.
An additional advantage of this growing on hydro grains, compared with ordinary potting soil, is that you can easily use a water meter to indicate when you need to give (nutrition) water. This way you rarely give too much, or indeed too little water. As a result of the use of hydro grains the chance of fungi, mildew, and other plant diseases becomes minimal. Another advantage is that several plants can be put together in a flower box. In ordinary soils plants of different sizes would have different needs for water. When growing on hydro grains each plant absorbs just as much water and food as it needs. In short, hydro grains are OK for growing!