So, does a sheep wool mat do what it promises? Do slugs and snails crawl over it or not?
The following experiment was set up:
Sheep’s wool mat was laid out in a U-shape and weighted down with bricks on the sides.
I had already had the experience that snails simply crawl under obstacles during the day to hide.
By weighing them down with bricks, this was made impossible.
Afterward, about 23 slugs were placed in the middle and what happened next was recorded in a time-lapse video.
Video: Snail & Slug Deterrent Mat in the Test
In the video, you can see that the test did not give a clear result.
You can see that the slugs are really “slowed down” in their movement. But at the same time, you can also observe how some of them finally overcome the barrier.
However, they did this at the thinnest point, and it can be seen that the width of the barrier plays a role in its effectiveness.
When the snails crawl over the wool, they bump with their fine antennae into individual hairs, which they obviously cannot recognize. This disturbs them, they retract their antennae abruptly, and some of them turn back.
Tests with fresh sheep’s wool showed similar results. However, this was clearly more effective than the mat. However, it lost its effectiveness over time due to rainfall. Whether this is also the case with the wool fleece remains to be tested.
In the United States, you can order fresh sheep wool here: Offer on Amazon.com.
Advantages
One advantage is that this is a form of natural slug defense and no poison is used.
At least a small effectiveness has been confirmed in the first trial.
The wool mat is also approved for organic horticulture.
Like any mat, it also comes with the advantages that it minimizes weed pressure somewhat and stores moisture.
Disadvantages
Some slugs were slowed down, but not prevented from crossing.
One slug also immediately hid under the mat on the other side. To prevent this behavior, the sides must be weighted down with stones or similar.
Otherwise, the mat blows away or might be stolen by animals as nesting material.
There are reports that squirrels and birds have stolen the wool. Cats are also said to have been attracted to the soft material.
Conclusion
So, the evaluation is ambivalent.
An effect could clearly be observed. Some slugs were not only slowed down, but also deterred. But others were persistent and crossed the obstacle without major problems.
Therefore, it can be used as a complementary measure, but it should not be relied on alone.
It could be used, for example, in entrance areas of greenhouses where it is also protected from rain.
However, if you have no possibility of getting fresh new wool and snail fences are out of the question for whatever reason, then sheep wool mats are worth a recommendation with reservation.
At least the mats are relatively cheap and have some desirable side effects.
Alternatives
There are numerous other ways to protect a bed and individual plants against slugs.
The most sustainable way is to introduce the natural enemies of slugs into the garden. These include hedgehogs, amphibians, birds, and insects.
Potted plants and raised beds can also be protected relatively cheaply with copper. More on this here: Copper tape against slugs.
An electric snail fence is also conceivable as protection. If you have a little electrical knowledge, this is an effective means of protection.
Snail fences made of metal also provide good snail protection. They are particularly suitable for larger flower or vegetable beds.
