To stimulate plant growth, all you need is some rock dust. This is less a classic fertilizer and more a natural additive that is usually rich in silica, aluminum oxide, magnesium, iron, manganese, potassium and calcium. Important nutrients such as nitrogen, phosphorus and potassium are only found in small amounts in the finely ground rock. The use should primarily improve the soil quality and water retention capacity in the home garden – and thus automatically strengthen the plants. The primary rock flour is usually made from nutrient-rich lava rock, basalt or diabase, more rarely from rocks poor in nutrients such as quartz, zeolite and granite. These are used to improve soil storage capacity.
Urgsteinsmehl can and should be used in different ways, depending on the type of soil and which (weathered) stones and minerals are already contained in it. For rough orientation:
If the soil is sandy, it tends to be poor in nutrients and humus, since the rain washes the nutrients out of the upper layers of the earth. Here the nutrient content can be increased with alkaline primary rock flour. If, on the other hand, you use a flour based on bentonite, the formation of clay-humus complexes should be stimulated.
If the (moor) soil is rather acidic, the PH value can be raised with calcium-containing primary rock powder based on diabase and thereby neutralized. After that, garden plants feel much better.
Primary rock powder based on basalt (or granite), on the other hand, is said to help acidify strongly alkaline soils that are particularly rich in lime.
Alkaline soils, such as lawns, should be supplied with nutrients by adding primary rock flour from lava or basalt.
If you want to improve the activities in your compost, it should make sense to use primary rock powder based on diabase or lava rock.
And another tip: If you are not sure whether the soil is more acidic or basic, you can measure the pH value.
Since it is usually a fine to coarse-grained flour, the question arises as to how the primary rock flour should be used. Here you can choose between different methods, a few common ones are for example:
Note: The fine powder releases a lot of dust, so it is advisable to wear a face mask during use.
As far as the correct dosage is concerned, it is recommended as a rough guideline to add up to 150 grams of primary rock powder to one square meter of soil in calcareous soils and 200 to a maximum of 300 grams in acidic soils. As a rule, you will also find precise information on the respective packaging from the manufacturer. However, since it is not a classic fertilizer, you cannot over-fertilize the soil. It is also important to know that the roots can only absorb the trace elements and minerals when the primary rock flour has been completely decomposed. Accordingly, you should not expect a short-term effect immediately after use.
As mentioned at the beginning, the rock flour can not only help to promote the growth of the plants: it also makes them more resistant to pests. In addition, it should protect against fungal diseases. To drive away sucking insects such as aphids, it can be helpful to sprinkle the fine powder on the infested areas – for example using a powder bottle. Snails, on the other hand, should be able to be kept out of the beds by sprinkling the bedrock powder on the ground around the vegetables as a natural barrier (approx. five centimeters wide). To prevent plant diseases, it can make sense to dust the leaves to nip possible fungal spores in the bud – in the truest sense of the word.
And one more tip at the end: If you are making nettle manure, you can add the rock powder to neutralize the stench.
Sources: My Beautiful Garden, Utopia
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