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How can worms improve the soil structure?

Written by Maarten Casteleijn | Last update: 22-6-2021

A good soil structure is imperative in case of open field cultivation. If the soil has good physical properties, it is more suitable for plant growth. For example, it is important that the roots have enough space and are able to take up enough water and oxygen. Does the soil have a good large and small pores ration and is the bonding between the particles in order, then you are dealing with adequate soil structure. To improve the soil structure, you can make use of worms. In this article, we will explain this further. 

Types of worms

In nature worms naturally exist in healthy soil, 30 to 100 on average per square meter. There are three groups of worms: 
  • Worms that live in the top layer and predominantly feed themselves with leaves.
  • Worms that live in the upper 60 cm of the soil and eat both leaves and earth.
  • Worms that move vertically, down to deep inside the groundwater and mainly eat earth.

If there is sufficient food in the soil, the population can start growing. If there is too little food, too much salt in the soil or when the soil is too dry and becomes too acidic, the population will decline.


A worm will eat the equivalent of its own weight on earth and organic materials in just two days time. As the worms eat their way through the soil, the create tunnels. During this process they add all kinds of enzymes to the soil. Nutrients that were already in the soil, but are not in reach of the plant, are thus made available by worms. As a result the soil becomes lighter and has a better water management. In other words: the soil structure is improving. 

Adding worms to the soil

So in order to improve the soil structure you can choose to add worms to the soil. Almost always a mixture of different worms is used, because the features of the different worms reinforce each other. A mix of 75% Megrow worms and 25% dew worms can be applied in almost any situation. In case of very dense soil applying a larger percentage of dew worms to the mix may be helpful. These 'commuters' penetrate deep into the groundwater.

When introducing worms with the aim to improve the soil structure, stick to the following quantities:

Surface areaNumber of worms
1 m²10 grams
10 m²100 grams
100 m²1 kilogram
1000 m²10 kilograms
10.000 m²100 kilograms

Habitat of worms

To get the best result it is important that the worms are introduced under sound conditions. Worms like nutritious, humid soil with a pH of about 6.5. Just like snails they do not like soil that is too salty or too acidic and in case of acidic soil they will become less active. At a pH-value below 4 all movement will cease. Worms breathe through their skin, so they are sensitive to pesticides soluble in water, but there are especially bred worms that are more resistant to this. 

Additionally worms are productive within a wide temperature range. The eggs of worms stand a chance of survival when steaming of the soil is applied and dew worms can feed to deeper layers. Worms become less active at temperatures below 4 degrees Celsius. Above 30 degrees the worms will only quickly come above the surface to eat. 

Introducing worms

Introducing worms is very easy. The worms are in 5 kg packages, in a breathable bag with around 3 kilos of food and a cooling element. After opening the box and the bag you take the box into the greenhouse place a handful of worms after every 1 or 2 meters. The worms will quickly spread afterwards. Since they are not in favor of light, the first worms will enter the soil after only 5 -10 minutes. It helps if the top layer has an open structure. 

Once in the soil, the worms will go to places where food can be found, which may be as far as 10 meters farther. So the worms do not need to be positioned at the far edges. The worms were put into the box maximally 24 hours in advance and they should be positioned immediately after arrival.

Questions about the improvement of the soil structure using worms

Do you have any questions about improving the soil structure using worms or would you like customized advice? Then ask your question using the form below. We will contact you as soon as possible - even within 24 hours on workdays.

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Maarten Casteleijn About Maarten Casteleijn

Maarten Casteleijn is a product specialist in plant resistance at Royal Brinkman. In addition to experience in horticulture, he also has experience in teaching and coordinating research in the medical sector. By combining his work experiences, he can look at a problem with different perspectives and think out of the box. Maarten says that his passion is reflected in his work experience: receiving and sharing knowledge. "I have a broad interest in innovation and sustainability. Together with the grower, I want to achieve a final zero discharge by increasing plant resilience". 

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