Worms not only find optimal living conditions outdoors, but especially in the cold winter and damp spring months, they are often drawn to the potting soil of plants. Once they are there, they usually do not go away on their own. Although they certainly have advantages, the disadvantages usually outweigh the disadvantages and combating them is advisable. Chemistry plays a less important role.

Pros and cons of worms

A worm in the potting soil is usually considered a pest. This is only partially true, because it also presents itself as a beneficial creature.


  • their excretions act like fertilizer on the plants
  • dead plant parts serve as a source of food and there is less smell of rotting
  • by eating dead plant parts, they destroy bacteria that could damage the plant
  • their movements loosen and aerate the soil
  • the loosened soil can absorb moisture better and reduce the risk of waterlogging
  • Humus is distributed more evenly in the soil


  • most worm species reproduce rapidly
  • little dead plant parts in pots allows them to feed quickly from roots due to lack of food
  • damage roots by nibbling and disturbances in the water and nutrient supply can occur
  • are disgusting to many and are usually interpreted as unhygienic
  • if the infestation is severe, affected plants may die

Fighting different types of worms

There are countless species of worms that, as invertebrates, have an elongated, round or flattened physique. The vermes, as the class of all worms is called, show different colors depending on the species. These range from glassy/transparent, through white, pink, reddish to green, brown or black. Most are related to earthworms (Lumbricidae). This makes targeted control easier because they react equally to the different methods. An exact identification of the present worm species is therefore usually not necessary.


A vermes should not be confused with an insect larva, which nevertheless often happens. Larvae can be clearly identified as insects because they are visually distinguished from worms by their legs, antennae and chitinous armor. Although some combat methods also work on larvae, the shell in particular offers them special protection against “attacks”.

It should be noted that larvae also hatch from the eggs of worms, but these are not classified as insect larvae.

Control agents from specialist shops

There are many different pesticides on the market to control worms in potting soil. Whether sprays, tinctures or solutions for pouring, the selection is large. In most cases, these are chemical preparations. It is well known that chemical pesticides pollute the environment. They can also trigger allergies and make life unnecessarily difficult for allergy sufferers. Organic products are hard to come by. The company BAYER has developed a promising preparation “BioAct”. The main ingredient is a fungus that attacks the worms and causes them to die. So far, however, the product has only been approved in Greece.

sticky traps

If the worm infestation is low and the worms are discovered quickly so that they have not yet settled deep in the ground, sticky traps from specialist retailers can help. These are so-called yellow stickers or yellow boards. They have an adhesive surface to which they are held on contact. The adhesive strips are stuck into the potting soil. They mostly only work on the surface of the earth. Sticky traps are also effective against parasites.

Practical control methods

Worms can be combated without any chemicals as follows:

Swapping the potting soil

If worms are discovered in the potting soil, due to the usually rapid rate of reproduction, action should be taken quickly and the plant removed from the soil. To do this, proceed as follows:

  • create a pad of newspaper or kitchen paper to catch any worms that fall out
  • Carefully pot the plant over the paper
  • Remove roots from soil as completely as possible
  • lightly “tapping” the roots facilitates soil removal
  • Hold the roots under a jet of water so that even the smallest bits of soil with any worm eggs can be washed away
  • Dispose of soil from the pot in the residual waste or in the organic waste bin (worms can do useful things in the garden)
  • Either exchange the pot for a new one or thoroughly clean and disinfect the old one
  • A commercially available household disinfectant is sufficient for disinfection
  • Fill in fresh, new soil and repot the plant

Potting soil cleaning using an oven

Whether soil infested with worms is to be cleaned and reused, or new soil is to be used, the oven method is recommended. Especially when buying cheap potted plants and/or potting soil, worms can already be included. This procedure helps to ensure that the earth does not become unusable:

  • Preheat the oven to 220 degrees Celsius
  • Line a suitable baking tray with parchment paper or aluminum foil
  • Spread the potting soil evenly on the baking sheet
  • the layer of soil should not be higher than two inches so that the heat reaches the bottom
  • Put the baking sheet with the earth in the oven
  • “Cooking time”: between 15 and 20 minutes
  • there should always be an eye on the oven in order to be able to react quickly if the earth should start to burn
  • After the “baking time” has elapsed, allow the earth to cool down
  • burned worms are barely visible – if they are, they can be easily picked up
  • the potting soil is cleaned and can be used normally
Tip: The kitchen window should be open during the process so that the smell of burnt earth, which is often perceived as unpleasant, can escape to the outside.

microwave method

The microwave method works in a similar way to cleaning the earth in an oven. With this, potting soil is reliably freed from worms. The advantages over the oven method are lower power consumption and time savings.
Proceed as follows with the microwave method:

  • Slightly moisten the soil (must not be soaked)
  • Pour soil into a bag or onto a cotton cloth
  • close/tie tightly
  • Place the earth in the middle of the microwave plate
  • Heat for about six to seven minutes at 600 watts – heat for about four to five minutes at 900 watts (highest cooking level)
  • the process is observed in case the cotton catches fire
  • then allow the soil to cool down and only then open the bag/cloth
  • the soil is worm-free and can be used without hesitation

collect worms

Depending on the extent of the worm infestation, collection can be carried out. This measure is only suitable to a limited extent, since only the worms are removed. The eggs remain in the ground. This means that a one-off collection is not enough. It has to be done several times at regular intervals.
Instructions for collecting:

  • Submerge the pot with the plant in a bucket of water (the pot must have a drainage hole)
  • the water level is just above the surface of the earth
  • after soaking the earth, the worms come upstairs to escape drowning
  • collect worms on the water surface
  • Worm eggs are protected in the cocoon – therefore repeat the process several times at intervals of a few days
  • always allow the plant to dry thoroughly afterwards
Tip: Gloves protect against the bites of some types of worms.

Desiccation control

Plants that do well with dry potting soil can be rid of worms by drying them out.

All worm species need their skin to have a certain level of moisture. They achieve this in the earth through the moisture present there. If this is missing, it will dry out. The worms die.

The process goes relatively quickly. They usually do not survive two to three days in a completely dry soil. This method is only suitable for plants that don’t mind dry soil for a few days. Dwarf peppers, cacti and the zamioculcas, for example, cope well with short dry periods. With plants whose soil should only dry for a short time, there is a risk that they will wither.

home remedies

In addition to practical methods for fighting worms in the potting soil, the following home remedies have also proven to be effective:


Worms do not like or tolerate sulfur. They choke on it and avoid places with a sulfur smell. For this reason, sulfur is also suitable for prevention.

Sulfur can sometimes lower the pH of the soil. But dosed in small amounts, it usually does not harm potted plants.

Sulfur fertilizer is not suitable for every type of plant. It is best to use burnt matches. Simply stick six to eight of these upside down in the potting soil and swap out for new ones every three to four days. By the way, this method also helps against insect larvae.


Silica Sand and Gravel
In order for a worm to damage a plant and lay eggs, it needs to get into the soil. The path can be made more difficult for the worms by laying out a layer of quartz sand and/or gravel about two to three centimeters thick on the surface of the earth. These materials do not mix with the soil when watering, making them ideal for permanent prevention.

Potting soil substitute
As a preventive measure, switching from conventional potting soil to hydroponics or clay granules, such as those offered by Seramis, is a good idea. Especially for plants that need constant moisture, these two alternatives offer an optimal solution to prevent worm infestation.

Worms in the potting soil are not to be regarded as pests in the strict sense. Nevertheless, fighting is advisable. This does not require the use of chemical agents. There are some environmentally friendly alternatives that work just as effectively and are described in detail here. Once worms have settled, the conditions are optimal. Therefore, it is important that preventive measures are taken to avoid re-infestation.

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