pH is the measurement for the acidity or alkalinity of a solution.
Microbes at pH neutral.
For an optimal life of microbes in the soil, the pH value of soil and water should stay neutral. Microbes convert organic water-soluble fertilizers into nutrients. However, for the absorption of trace elements (iron, boron, manganese, zinc, copper, molybdenum, silicon) a neutral pH value is too high. That is why a pH value of between 5.5 and 6.2 is recommended.
Acids reduce the pH value.
The pH of tap your nutrient sulotion should be measured and kept at 5.5 – 6.2, depending which medium is used. Tap water usually has a high pH value and can be adjusted with pH-plus, pH-down or even citric acid. The pH of potting soil may be very high, because it affects the pH of the liquid in solution. That is why it is important to keep the pH of the tap water always at 6.5. The pH value of the soil should not fluctuate continuously.
The pH value should be stable.
It is proven that the roots are getting used to a certain acidity. This is quite obvious, because the pH value is an important physiological factor of the specific ‘roots climate’, from which the plant develops. It is better not to change the original acidity of the soil. An instable pH value causes the roots to be unable to absorb nutrients. Sometimes the acidity of the soil is changed accidently, because some substance is added to the water without testing the pH value afterwards.