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Acidic soil is important for many plants in order to enable species-appropriate site conditions that improve growth and maintain the health of the plant. Many of the soils in Germany are normal or slightly acidic, but only a few soils are really acidic, most of which are located in unused nature reserves. Therefore, the gardener has to help himself and lower the pH value. Those who do without peat can benefit from other methods.

acidify the soil

Why acidify soil?

Every plant needs a different form of soil in which it feels comfortable. This is mainly defined by the natural distribution of the species, which calls the soils found there their own. There are therefore a large number of flowers and fruit-bearing plants that prefer acidic soil, which is difficult to find in Germany and Central Europe in general. Lime is one of the main culprits here, as lime raises the pH value of the soil and thus offers ideal conditions for local fruit and vegetables. However, some plants in particular, including ericaceous plants, depend on a pH below 5.5, including the following.

  • rhododendron
  • blueberry
  • heather
  • cranberry
  • cranberry
  • camellias
  • kiwis
  • Japanese Azalea
  • rosemary heath
  • Broad-leaved laurel rose
Blueberries on the bush

This form of soil is particularly necessary when growing blueberries in your own garden. An acidic site is typically achieved by adding peat, but more and more gardeners are refraining from using this organic sediment as it is ecologically unsafe. For this reason, there are numerous alternatives and methods to lower the soil pH value and not have to rely on peat.

Notice: Be sure to refrain from using vinegar as a remedy because, despite the immediate effect, it will only have negative effects on the soil. The acetic acid kills important microorganisms that are essential for the healthy growth of the plants.

PH value

Check the pH yourself

Since the soil in Germany is hardly acidic, it is still worth determining the pH value of the location before using a peat alternative. This gives you an overview of how acidic, alkaline or ideal your soil is and you can determine the dosage of the acidifying agent more precisely. The following methods are offered for this.

pH test strips

With special test strips, which are also used for groundwater and irrigation water samples, a very good analysis of the soil composition in terms of acidic and alkaline can be made. These are used as follows.

  • prepare a sample of soil, which is stretched with water
  • dip the strip into it
  • wait for the strip to change color
  • the color indicates the pH of the soil
  • Cost: 3-5 euros

pH soil tests

This variant is similar to the test strips, but more accurate and takes a little longer. In addition, it is connected to more utensils, all of which are already present in the kit. The instructions are described below.

  • collect several soil samples from the site at different depths
  • mix them well
  • put part of the soil in the test tube or container
  • add distilled water
  • the reactant is added, usually a tablet
  • cap the container and shake well
  • then a color is displayed
  • this color indicates whether your soil is basic or more acidic
  • Costs: 6 - 20 euros, Neudorff for example 6 euros

Vinegar and Baking Soda Test

The vinegar and acid test is the variant with the most inaccurate results, but gives a pretty good idea of whether your soil is acidic or basic.

  • for this you take a soil sample in sufficient quantity
  • add acetic acid and baking soda to the soil sample respectively
  • if you hear a hiss from the baking soda, the sample is more acidic
  • if you hear a hissing noise when you hear the vinegar, the sample is more alkaline
  • Cost: 0.2 - 2 euros
Vinegar and Baking Soda Test

Notice: The higher the level goes in the alkaline direction, the more of the treatment is needed to make the soil more acidic. Depending on the agent used, this can take several weeks.

soil analysis

Scientific soil analysis

Of course, you can of course also go the route of a professional soil analysis, but this is associated with higher costs. To do this, simply send a soil sample to a laboratory that specializes in this form of analysis. You will then receive precise information about the existing pH values and can therefore use the appropriate agent for processing. Depending on the laboratory, the costs here are between 50 and 80 euros.

soil condition

Before using a gate alternative, it is advisable to check your own soil in the garden and thus get a more precise picture of the necessary addition. There are two specific types of soil that need to be treated differently.

  • loose soils, good drainage
  • compacted soils, loamy

While loose soil that has effective water uptake and release is best enriched with organic materials, the situation is quite different in dense clay soils. Here, organic matter would make the soil more alkaline and thus do the exact opposite of what is desired. Mineral materials have to be used for this so that the compacted soil is adapted, but not changed in its composition or even permanently reduced.

alternatives to peat

Peat isn't the only material you can use to lower soil pH. Nature provides a variety of materials that have acidic properties and work the soil effectively over a period of several days to weeks. They have the advantage that they do not destroy the sensitive bogs from which the peat soil is extracted. Even small amounts of this sediment contribute to the destruction of important habitats for flora and fauna and therefore the following alternatives can be mentioned that are just as suitable without being harmful to the environment.

  • grape pomace
  • coniferous earth
  • special compost
  • oak leaf compost
  • mulch layer
  • coffee grounds mixture
  • iron sulfate
  • sulfur

grape pomace

Grape pomace is the solid residue of pressed grapes used in winemaking. The vegetal residues of the wines are an excellent material for lowering the pH of the soil as they contain pure grape acid and ferments. Since the pomace is not artificially produced, it can easily release the acid to the site without destroying important microorganisms. However, grape pomace can only be obtained from winegrowers.

coniferous earth

It gets easier here with coniferous soil. Coniferous soil is the soil in the immediate vicinity of coniferous trees. Coniferous trees have the property of acidifying soil and for this reason it is worth using the coniferous soil around the trunk. You can easily fill up the coniferous soil around the coniferous tree with the garden soil from the planting site.

special compost

This special compost is an effective mixture of several organic components that together have an extremely acidic effect. The compost consists of parts of coniferous wood, including the bark, needles and wood flour, horn shavings, coffee powder and leaves of chestnuts, oaks and walnuts. These are used together and can then be distributed in the planting soil. In addition, this compost has an extremely good fertilizing effect.

oak leaf compost

You can also simply choose a compost made from oak leaves. Pure oak leaves are extremely acidic and as they decompose, they begin to release even more acid, which has a positive effect on the soil. Even small amounts of this pure compost have a strong and non-negative effect on the earth. In addition, oak leaves are easy to get in Germany, especially if you have an oak tree in your garden yourself.

mulch layer

This mulch layer consists of a mixture of crushed softwood of different species and also oak leaves. The properties of the conifers are themselves effective through the wood and are reinforced through the oak leaves. Apply this mulch to the site or soil in a thickness of two inches and additionally fertilize with an organic nitrogen fertilizer. Horn shavings are particularly suitable for this.

Special blend based on coffee grounds

Here the coffee grounds are an important substance to improve the acidic properties. Along with the coffee grounds, crushed coniferous wood, the associated needles and chopped oak leaves are used. A nitrogen-based fertilizer must also be used with this variant in order to increase the effect and at the same time to supply the plants with the necessary nutrients.

coffee grounds

iron sulfate

Iron sulphate is an alternative to peat, which can be used primarily for compacted clay soils. Iron sulphate is not an organic substance, but a salt of sulfuric acid. The sulphate acts extremely quickly in the soil and develops an acidity that can lower the pH value of the soil by a whole unit within two weeks. The only drawback are possible rust spots on clothes and paths.


Sulfur is an element that can also be used in compacted soils and acts there over a period of several months. Sulfur should therefore be used in the previous season so that the soil can be used immediately for planting the crops in the following year.

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