Algal Lime: Advantages And Application Of The Natural Fertilizer

Last updated on October 23rd, 2023 at 08:39 pm

Algal lime is an ecological garden fertilizer and is used to improve the soil climate. In this article you will learn interesting facts about it.

What is algal lime?

Algal lime is made from the dead sediments of red algae and is mainly used as a garden fertilizer. As the name suggests, it contains a lot of lime, which raises the pH of the fertilizer. Therefore, you should not use algal lime in lime-sensitive soils or on acid-loving plants (such as rhododendrons).

Algal Lime: Advantages And Application Of The Natural Fertilizer

Red algae are found primarily in oceans. There are also a few freshwater species that grow mainly in rivers and streams. The majority in Europe comes from the North and Baltic Seas, which is why algal lime is particularly suitable as a fertilizer in northern Europe.

Algal lime consists of 70 to 80 percent calcium carbonate, about six to ten percent magnesium carbonate and about four percent silicic acid and some trace elements.

You can use algal lime to improve your soil and prevent what’s called “soil fatigue.” You can also enrich your compost with some algal lime every now and then. This is especially useful if you use the compost in your vegetable garden.

Advantages of algal lime

Algal Lime: Advantages And Application Of The Natural Fertilizer
  • The trace elements contained, such as boron, iodine and manganese, strengthen the plants.
  • Algal lime promotes the activity of microorganisms and thus leads to healthy, biologically active garden soil.
  • It also provides natural protection against insect and fungal attack. Pests such as mealybugs or chiggers could otherwise infest your plants.
  • The soil is said to warm up faster in spring due to algal lime, so that microorganisms in the soil become active more quickly.
  • Compared to chemical fertilizers, vegetables and fruits fertilized with algal lime are even said to taste better.
  • Algal lime releases its nutrients more slowly than synthetic fertilizers. This protects the soil.
  • The production of synthetic fertilizers is also associated with high emissions as well as resource consumption. Nitrogen and phosphorus can have a negative impact on water and soil. Some fertilizers also contain heavy metals that are not needed by plants.

Application of algal lime

This is how you can fertilize with algal lime:

  • Algal Lime: Advantages And Application Of The Natural FertilizerFirst determine the pH value of the soil. You can buy test strips online for this purpose. The instructions for use of algal lime state at which pH values you can use how much algal lime. If the soil already has a high pH value, algal lime is not recommended.
  • You can buy algal lime at the hardware store. On the packaging is a dosage instruction printed, which you should follow exactly. Be careful not to overdose the algae lime, otherwise nutrients will be massively degraded.
  • Apply the algal lime evenly, preferably in spring. You can also mix in some compost. This helps the plants to better absorb the nutrients.
  • For lawns, you can spread the algal lime with a fertilizer truck. Under shrubs and on beds you should simply spread the fertilizer with a shovel. Work the algal lime well into the soil so that the powder is not blown away.
  • Finally, water the plants lightly so that the lime is quickly absorbed.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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