How does the pH have an effect on the growth of plants?

In principle, the pH of the soil influences the availability of the nutrients. A pH of 5.5 – 6.5 is recommended for peat substrates. Lower or higher pH values can lead to nutrient regulations. The pH can change due to acidic or basic fertilizer or water containing calcium carbonate during the course of cultivation.

Aluminum or manganese ions get soluble at a low pH. Al ions play an important role in the blue tint of hydrangeas.