Do not fertilize hydrangeas with rock flour

What is rock flour?

With so-called rock flour, too bedrock meal called, it is one natural soil conditioner from volcanic rock. It contains minerals such as calcium, iron and magnesium, but no phosphorus, sodium or potassium, which are commonly found in fertilizers as they support plant growth. Rock flour is therefore not a fertilizer in the true sense of the word, but it can be used to improve the soil in the garden.

Is rock flour good for hydrangeas?

Rock dust is suitable due to its alkaline properties not for hydrangeas. Even the relatively acidic basalt rock flour has a too high for hydrangeas PH value on. Similar to the application of lime, which is also contained in small amounts in rock flour, if the soil is too alkaline, hydrangeas can no longer optimally absorb the nutrients from the soil.

Tip

These plants love rock flour

While not recommended for use on hydrangeas, rock dust is suitable for many other plants in the garden. In particular, heavy consumers such as tomatoes are happy about the extra portion of minerals and the deacidification of the soil.