Wood ash in natural fertilizers is not uncritical
According to experts, the disposal of large amounts of wood ash in compost is not entirely unproblematic. This is due to the composition of the gray powder.
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- So that the compost can work in winter
- Can ash be put on the compost?
Wood ash consists of:
- 25 to 45 percent quicklime (calcium),
- 3 to 6 percent magnesium and potassium oxide,
- 2 to 3 percent phosphorus pentoxide,
- as well as traces of iron, manganese, sodium and boron.
- Depending on the origin of the fuel, there may also be heavy metals such as cadmium, lead and chromium. Sometimes even in critical quantities.
Therefore should Ashes as fertilizer can only be used sparingly in the garden. If you compost all of the ash in your household, the valuable fertilizer will inevitably be enriched on one side with the substances mentioned above.
What are the implications?
Due to the high pH value, this fertilizer would no longer be ideal for the garden. Spreading the compost is then like liming the soil. In agriculture, such fertilizers are only used to improve bare, very loamy soils.
In addition, without analysis, you will neither know the exact proportions of trace elements nor how high the proportion of heavy metals is. Doing so can result in the Garden soil accumulate unintentionally with toxic substances.
Less is more
As is so often the case, the following also applies in this case: A little ash in the compost can improve the quality. Too much, however, must be avoided at all costs. The following applies:
- Only add ashes from untreated woods to the compost. Lacquer, glue or the plastic coatings of glossy magazines can contain dangerous, toxic substances.
- Only use firewood of the origin you know. If the tree was on a busy road or in an industrial area, toxic heavy metals may have accumulated in the bark and in the wood.
- Natural fertilizer enriched with wood ash is ideal for loamy or clay soils. This fertilizer can be used to get the high pH values under control.
- Sprinkle just a fine layer of the gray powder in the compost and cover it with a thick layer of green material.
Tips
You should always dispose of ashes from the charcoal grill with household waste. This ash contains grease residues, such as acrylamide, which has fallen into disrepute. These substances have no place in the garden soil.
