We all know woodlice. The small animals that are about 1 cm long and have a brown to grey, flat oval and slightly curved body. When danger threatens, they roll up into balls and lie lifeless.
Woodlice do not often cause us any problems in the garden. On the contrary, they decompose dead plant material and are therefore very useful.
However, populations that are too large can become a nuisance in beds and plant pots so, we will have a look at how to get rid of woodlice in the garden.
What are Woodlice?
What some of you may not know is that woodlice are not insects, woodlice are in fact Isopods which are crustaceans. So, they are descended from species that lived in the sea but have now adapted well to life on land and their history is said to go back 100 million years.
In addition to the tracheae, with which they can absorb oxygen from the air, woodlice still even have rudimentary gills although these have receded to such an extent that the animals would drown in the water.
What do Woodlice Look Like?
In the UK there are 30 species of woodlouse, and they are small, oval, and flat animals that reach a body length between 14 and 20 millimetres. They are usually grey coloured, but they can also be shades of brown, yellow and a mottled appearance of both.
The underside of the body and the legs of the woodlice, on the other hand, are yellowish to white. Their eyes are recognizable as a dark grey to black dots.
There are two pairs of antennae on the head, but only one is visible. Characteristics of the woodlouse are their finely jagged, semi-ring-shaped back armour, the 14 legs and twelve so-called split feet.
In the event of danger, the animals pretend to be dead (shock rigidity) and roll up into a ball like a hedgehog.
Can You Poison Woodlice?
No, you should not poison woodlice, since woodlice play an important role in a functioning ecosystem, you should definitely refrain from fighting the little animals with poison.
Especially since many poisonous baits (scatter baits) not only destroy isopods but also other crawling animals and can pollute the drinking water.
Instead of poisoning the little garden helpers, there are simple ways to drive woodlice out of the house and flower beds.
How to Get Rid of Woodlice in the Garden
Woodlice are hard-working helpers in the garden that should not be fought. They decompose dead material and thus ensure a good supply of humus to the bed and soil. Nevertheless, many people cannot stand the primaeval crawlers and want to get rid of them.
1. Natural Predators
If you have a large number of woodlice, one can hope for the help of natural predators. In a natural garden, the number of woodlice should regulate itself. A Woodlouse’s natural predators include spiders, frogs, toads, hedgehogs, moles and songbirds.
Try to attract and settle these beneficial animals with a natural garden with sufficient nesting and hiding places. Hedges, piles of leaves and lush pond plantings are just a few examples. If the garden is animal-friendly, the wild animals gather voluntarily and destroy excessive populations of woodlice in the garden all by themselves.
Woodlice even make it comparatively easy for their enemies – because they are very sociable animals that like to settle in large groups and are therefore easy prey.
2. Trap and Relocate
The easiest way to control woodlice is with natural bait. Place a hollowed-out potato or carrot in a shady, damp place where woodlice live. A collection container filled with old fruit, damp leaves or compost, or an upturned flowerpot also serves as suitable bait.
Alternatively, a small damp kitchen towel that is crumpled up and placed on the floor is sufficient.
When the woodlice have gathered at the bait, you can collect the animals with a shovel and broom, carry them to a suitable place and release them there again. For example, the composting bin is ideal for this, because the small animals work well through the soil here.
Note: If you want to get rid of the woodlice completely, you can dispose of them together with the bait in your garden waste bin.
3. Keep Areas Dry
One of the most important measures in getting rid of woodlice is to keep affected areas dry. As a precaution, you should make sure that there is sufficient water drainage when you buy plant pots, balcony boxes and the like.
In this way, you avoid waterlogging in tubs and pots. The damp, mouldy earth magically attracts woodlice. A close examination of the plants for rotten roots or plant parts and fresh, not too wet soil is the best protection against having too many woodlice in the garden.
Woodlice do not tolerate drought at all. It causes the animals to move on and look for a new home.
Sage is a herb that is often used in cooking to add flavour to food. It has a strong, pungent odour that some people find unpleasant. The leaves and stems of the sage plant contain essential oils that give it its characteristic smell.
Sage is a great woodlice repellent in the garden. Many insects and other animals have a sense of smell that is much better than ours, and they can often detect things that we can’t. In this case, sage produces a strong bitter scent that keeps woodlice away.
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Where do you Find Woodlice?
Woodlice depend on high humidity and settle in compost or in damp and shady/dark hiding places under stones and deadwood. During the day they like to stay hidden, and you will rarely see them running around freely in the garden. They become active at night when temperatures drop, and humidity rises.
It is likely that we all have woodlice in our gardens and they sometimes they also find their way into cold frames, greenhouses, planters or even inside our houses in basements and storage rooms.
Woodlice that invade houses can be annoying but not harmful – especially since, according to current knowledge, the animals do not transmit any diseases.
The woodlouse spends the winter in a frost-proof hiding place, where the animal hibernates.
What do Woodlice Eat?
Woodlice mainly feed on dead plant residues, which supports the valuable process of humus formation and returns the nutrients that the plants have withdrawn from the soil to our ecosystem.
When found in extremely large populations and when food is scarce, woodlice sometimes infest beds and weaken the vegetables there, by feeding. Therefore, the animals are often referred to as vermin and fought aggressively with baited traps or even poison.
In rare cases, woodlice also attack fruits that are ready to be harvested, such as potatoes or peppers, and eat tunnels in the vegetables. They have also become known as pests by gnawing on stored food in the house.
Are Woodlice Pests?
No, woodlice are not pests unless they are found in very large numbers. In fact, woodlice are so-called first disposers (decomposers). The small animals process dead organic matter in the garden and are therefore important helpers in the ecosystem.
By transforming garden waste into valuable humus, the activities of woodlice are an important part of soil formation (humification). The animals ensure healthy garden soil. In addition, the useful garden helpers are an important and calcium-rich food source for many songbirds and other wild animals.
How do Woodlice Breed?
For reproduction, the females are mated with the male woodlice and lay their eggs. They are carried by them in a breast pocket filled with liquid for 40–50 days before the young larvae hatch. After leaving the brood pouch, they are still significantly smaller and lighter in colour than the adult isopods.
In addition, their shell is still relatively soft, which is why they are particularly sensitive to drought at this stage. It usually takes 3 months for them to be fully grown and sexually mature. During this time, they go through a total of 14 moults.
Depending on the age and size of the female as well as the season, up to 3 generations with 70 young animals each can be carried out each year. Their average life expectancy is 2 years.
Woodlice occur naturally in every garden and also in the house, especially in the basement. However, since the little animals like to stay in dark environments with high humidity, they are rarely seen walking around freely.
The small crustaceans can often be found under stones and plant pots and in garages and laundry rooms. But the woodlice also feel very comfortable in the greenhouse and in cold frames.
Of course, there are also special pesticides for domestic use to combat isopods. In the trade, stomach poisons, sticky traps and contact poisons are offered. It is much more important to get to the bottom of the cause and eliminate it in order to permanently get an infestation under control.
Garden Doctor Tips
“Keep areas dry, woodlice need moisture on their underside, so they seek out damp spots!”
“Woodlice love your compost pile and are part of the healthy flora and fauna in your garden!”
“It is best to let potted plants that are already infested dry out completely for a short time and the woodlice will move on!”
“Do NOT use poison on woodlice – poisons will do more harm than good to the eco-system and can even get into water supplies!”
Frequently Asked Questions
Are woodlice vermin?
No. For the garden, woodlice are important soil conditioners that keep beds clean. If woodlice occur in very large populations, they should be attracted and relocated.
Can woodlice bite?
No, woodlice don’t bite. Their feeding tools are not suitable for penetrating human skin.
Do woodlice transmit diseases?
Woodlice do not transmit diseases to humans, animals or plants.
Are woodlice protected?
Woodlice occur in large numbers worldwide and are not under protection in the UK.
What attracts woodlice in the house?
A larger population of woodlice in the house can be an indication of excessive humidity. Close basement windows with fly screens and do not store fruit or vegetables open. Gaps and cracks in walls and floors should be sealed.
Can I vacuum woodlice?
It is not recommended to vacuum up the woodlice with a vacuum cleaner, since the animals will find more than enough food in the bag to continue to multiply there.
Hi, I’m Trev and I’ve been growing things since I can remember. When I was younger, I grew up on a farm, so I have always been around plants and animals. After studying horticulture at university, I decided to start my own nursery which I have run now for 25 years. In my spare time, I run this website – which is a resource for people who want to learn more about their gardens.