Over time and with increasing age, most garden soils acidify. To counteract this, gardeners regularly apply lime to their soil. Lime is a soil additive that rejuvenates the soil, promotes soil processes and thus improves the soil structure. In addition, the mineral calcium contained in lime is an important nutrient for plants and strengthens plant immunity. Read this article to find out how to apply lime fertilizer in the garden and what you need to bear in mind!
Lime mainly contains calcium, in different chemical forms depending on the lime fertilizer. Some limes also contain other nutrients and trace elements. Lime occurs naturally in many types of rock as calcium carbonate (carbonated lime) and is released in the soil through weathering. Therefore, lime, like all other nutrients, is used up and must be replaced. If no lime is added, your garden soil will acidify over time.
As soil ages, it is quite natural that the soil acidifies over time and the pH value drops. There are numerous reasons for this: in addition to natural acid inputs from plants or rain, gardeners also contribute to soil acidification through fertilizers, for example.
Our tip: Nitrogen fertilizers contain either nitrate or ammonium. Both fertilizers have an effect on the pH value in the soil. Nitrate has an alkaline effect, i.e. raises the pH value. Ammonium contributes to soil acidification as it lowers the soil pH. So if it is necessary to fertilize your plants with nitrogen-containing liquid fertilizer, use fertilizer with nitrate to prevent soil acidification.
Lime can be used to improve acidic and nutrient-poor garden soils. Nutrients, especially phosphorus, are not available to plants in an excessively acidic environment. This can lead to deficiency symptoms and poor growth. In addition, biological activity is lower, which slows down soil processes.
You should therefore regularly measure the pH value in your garden and lime if necessary to bring the pH value into an optimum range and keep it there. Nutrients are then most readily available to plants and fertilizers can be efficiently absorbed by the plants, which reduces environmentally harmful nutrient leaching. Biological activity is also boosted, humus is built up and the soil structure is improved. This reduces the risk of silting and erosion.
Soil type | Optimal pH range |
---|---|
Clay | 6,5 - 7 |
Sandy loam | 6,0 |
Sand | not under 5,5 |
Lime fertilizers such as garden lime, lime marl, algae lime and rock flour with mainly carbonated lime are well suited for the hobby garden. These lime fertilizers contain a lot of natural lime, which works gently and slowly in the soil, improving it in the long term. This is because these limes must first be broken down microbially before the nutrients become available to the plants and can take effect.
The soil is thus "fed" and builds up humus. This is good at first, but too much lime can leach out the soil in the long term. Too much biological activity can also lead to humus depletion and thus a decrease in soil fertility. You should therefore use lime with caution and always keep an eye on the soil pH.
In addition to the limes already listed, there are also quicklimes and slaked limes. These are fast-acting limes that react very aggressively in the soil and can even damage soil life in some cases. These limes are not suitable for hobby gardening and should therefore not be used.
Depending on the composition of your garden soil, there is a suitable lime fertilizer. In addition to classic limes such as garden lime, algae lime and marl lime, there are also rock powders. The effect and application of rock flours varies greatly, as they have an alkaline or acidic effect on the soil depending on the source rock. You can find out which rock flours are available and how to use them in the garden in our article on the subject.
Lime fertilizer | Application |
---|---|
Garden lime | Light to medium-heavy soils |
Calcareous marl | Particularly suitable for sandy soils (due to clay content!) |
Algae lime | Humus-rich garden soil; foliar application to strengthen the plant |
The aim is to keep the soil pH in your garden as constant as possible over the years. As most garden soils acidify over the years, you should lime regularly. In this way, you replace the lime that has been used by the soil and plants and partly washed out. This is called maintenance liming.
We hope all your questions about liming the garden have been answered. If you still have any questions or comments, please write to us at [email protected].
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Cover picture by Dr. Eugen Lehle on WikimediaCommons.
Marie is an agronomist. She is particularly interested in the sustainable and organic cultivation of vegetables and other plants. In her own garden, she gained experience and likes to try things out to learn from nature. She is particularly interested in the values and principles of permaculture, in order to contribute not only to the well-being of nature, but also to the well-being of people and future generations.
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