Plants need the right soil for healthy growth. But not every soil is naturally optimal, and the requirements of the plants can differ significantly from each other. The pH value has an important function here. Many plants thrive exclusively or best in soil with an acidic pH. But what if this value is too high?

Need to acidify the soil

The pH of the soil tells you whether the soil reaction is acidic, neutral or basic (calcareous). An unfavorable or incorrect value can lead to stunted growth and deficiency symptoms in the plants. Depending on the type of planting, it is all the more important to lower a value that is too high.

  • Many plants prefer slightly acidic to neutral soil
  • The pH of such soils is between six and seven
  • Some plants require a rather acidic soil
  • Value of acidic soil is between 4 and 5.5
  • They contain hardly any lime and a lot of humus
  • So-called ericaceous plants in particular thrive here
  • These include rhododendron, camellia, azalea, laurel, heather and rosemary
  • Or useful plants such as blueberries, lingonberries, cranberries and kiwi
  • They can only absorb nutrients in appropriately acidic soil

In most gardens in Germany, the soil is normal or only slightly acidic. Naturally acidic soils are found almost exclusively in untouched nature reserves. In the garden, you usually have to help to make the soil acidic. Before you can take appropriate measures, it is advisable to determine the actual pH value by means of a soil sample.

Soil analysis creates certainty

A soil analysis provides information about the pH value, the soil type and the nutrient content of the tested soil. It should generally be done every three to five years.

  • Best time for harvesting is late autumn or early spring
  • The easiest and most uncomplicated test is to use special test strips
  • Available in hardware stores, garden centers and pharmacies
  • Appropriate test strips, a small mason jar and distilled water are required
  • Tap water is rather unsuitable for this
  • Calcareous water would significantly affect the measurement result
  • For the test, add 100 g of a soil sample and 100 ml of distilled water to the glass
  • Close the jar and shake vigorously
  • Then let the whole thing stand for about ten minutes
  • Now dip the test strip into the liquid

The pH value can be read from the discoloration of the test strip. In addition to these test strips, there are other ways of testing the pH value of the soil, but these are a bit more complex and time-consuming. If the test reveals a pH value that is too high, you can lower it with various home remedies and make the soil acidic.

Home remedies to lower pH

There are numerous ways to make the garden soil acidic. For the sake of the environment, peat and chemicals should be avoided. In this way, sensitive peat bogs and thus important habitats can be protected. It is best to use suitable home remedies, some of which can be found in the home but also in nature.

Patience is required for a sustainable and natural lowering of the pH value. This process is relatively difficult and can only be done slowly and over a long period of time. To support this, you should avoid calcareous fertilizers and calcareous irrigation water. Organic matter is acidic when incorporated into the soil and decomposed there. Home remedies that can be used to make the soil acidic are coffee grounds, grape residue, coniferous soil, various compost mixtures or mulch.

waste products from wine production

If you live near a winemaker, you can use grape residue to acidify the soil. These waste products are produced when wine is pressed. The fermentation substances and pure grape acids contained therein are responsible for lowering the pH value. Unfortunately, you can only get hold of these waste products through a winemaker. Similar to coffee grounds, they also have a fertilizing effect. Therefore, they should not be applied in arbitrarily large quantities to avoid over-fertilization.

Certain plants

Some plants can also influence the soil composition or lower the pH value of the soil. They have a certain tolerance for alkaline or basic soils and usually prefer them. These include some evergreen shrubs such as boxwood or California lilac, deciduous plants such as forsythia, lilac and prairie squash, and some perennials such as hellebore (Helleborus).

However, these plants can only develop their effect if, after they die, the dead plant material remains on the ground and is returned to it in this way. What follows is a very slow drop in pH.

Tip:  This method is probably the most tedious way to acidify the soil. If organic substances are involved, patience is generally required.

coffee grounds

A household remedy that occurs in almost every household can increase the acidic properties of a soil and thus lower the pH value in a completely natural way.

  • Coffee grounds can be used pure
  • Or as a mixture with chopped coniferous wood or leaves
  • Coffee grounds contain many important nutrients
  • It is a valuable fertilizer, especially for ericaceous plants
  • Set mainly contains potassium, phosphorus and nitrogen in appreciable amounts
  • Work the dried substance into the surface of the soil
Tip: Coffee grounds should definitely be dried before being used, because damp grounds tend to go mouldy.


Mulch not only protects against unwanted weed growth and the soil from drying out, it also has an influence on the soil composition because it can lower the pH value. This can be a two to three centimeter thick layer of chopped wood from various softwoods including needles or oak leaves, as well as bark mulch , sawdust or lawn clippings. Lawn clippings should be slightly withered before spreading. After about two years, the mulch layer must be renewed.


If you need acidic soil, coniferous soil is the right choice. Coniferous soil is the soil directly under coniferous trees. It can be extracted and placed in the soil at the desired location, where it gradually makes it acidic. The removed soil can be refilled with normal garden soil. This method is particularly suitable for long-term results, because the decomposition process of organic materials takes a long time. For larger areas, the introduction of acidic humus made from chopped coniferous wood is recommended.

Tip: Coniferous soil should always come from coniferous trees in your own garden. Extraction from forests is prohibited.

Pure oak leaf compost

If you have a large oak tree in your garden, you have another useful helper to make the soil acidic. Pure oak leaves are a good alternative to special compost. It is very acidic in nature, which becomes even more so during the decomposition process. However, the composting process takes about two years. The finished compost is then worked flat into the soil.

Tip:  Leaves from oak trees on busy roads should not be used. It usually has a high pollutant content.

Special compost

Another inexpensive and environmentally friendly way to make the garden soil acidic with home remedies is to prepare a special compost mixture. This requires different organic components, which together have a strong acidic effect. The bark, needles and sawdust of conifers are mixed with the leaves of chestnuts, walnuts and oaks, as well as horn shavings and coffee powder. This special compost is also a very good fertilizer.

The pH value of the garden soil can decide whether plants thrive or die. It should be neither too high nor too low and should suit the needs of the plants in question. This is the only way to ensure healthy growth. Otherwise, it can be improved with various home remedies, which can take some time.

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