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Knowledge center Crop care Plant resistance How can worms improve the soil structure? 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.
Enzymes
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 area | Number of worms |
| 1 m² | 10 grams |
| 10 m² | 100 grams |
| 100 m² | 1 kilogram |
| 1000 m² | 10 kilograms |
| 10.000 m² | 100 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.