Fighting Slugs In The Raised Bed: 9 Really Helpful Tips

Last updated on October 23rd, 2023 at 08:58 pm

Probably the best known pest in the home garden is the slug, or more precisely the brown common slug.

This also makes it into the raised bed from time to time, so I was wondering how to combat slugs in the raised bed.

You can find out the best tips against slugs in raised beds here.

Depending on whether you want to take preventive measures against slugs in the raised bed, or are looking for immediately effective measures, the above tips for natural control of slugs are suitable in different ways.

Fighting slugs in the raised bed through preventive measures.
First of all, let’s look at preventive measures against slugs in raised beds.

This means that you can follow these tips and thus prevent slugs from getting into the raised bed in the first place or, if they do, make their lives as difficult as possible there.

1 Building a slugs edge or a slugs plate

If you are planning to build a raised bed but also if you already have one at home and have problems with slugs , it is recommended to install a slug edge or a slug plate around the raised bed.

The edge will keep the slugs from crawling into the raised bed. And yes, slugs can indeed climb the walls of a raised bed without any problems and fill their stomachs on top.

So it’s better to take precautions and install a slug edge that the slugs can’t get over.

Ideally, you mount the edge, for example, under the raised bed handrail, so that it is not so strongly heated by the sun and you can not burn your fingers on it when working in the bed.

A special slugs edge is usually not very cheap, but of course it provides very safe and long-lasting protection against the slugs.

2 Apply copper tape

Another tip against slugs in raised beds is to mount copper tape* around the entire bed.

It is best to mount the tape relatively far down near the grass, so you deter the slugs as early as possible.

Since copper is a metal, the copper tape can theoretically conduct electricity. However, it only does so if a power source or battery (similar to a pasture fence) is actually installed.

The fact that copper tape can still help against slugs is due to another property. Copper can release ions as long as certain conditions are met. These copper ions have a toxic effect on molluscs and thus also on slugs.

Especially the pH-value and the temperature have an influence on the effectiveness of copper tape. This means that an acidic environment and a temperature as high as possible are needed to develop the full effect of a copper band.

When the two come together – for example, due to the slugs’ acidic slime when the outside temperature is warm – the sole and copper react and the toxic copper ions are released. These keep the slugs from crawling further and spare your raised bed.

The actual effect of copper tape is debatable, because often the acidity in slug slime is not enough to trigger a reaction with the copper.

Nevertheless, copper tape works best against slugs for many amateur gardeners, especially if the widest possible tape is applied.

The advantage of copper tape is that it is relatively cheap and there are even self-adhesive variants for sale (for example, this variant from 13€*).

So if you have a large slug plague, it’s certainly worth a try!

3 Humus from the compost on slugs or quality soil buy

To keep your raised bed as free as possible from slugs, you should also pay attention to the purity and quality of the filling material. This is because slugs can sometimes get in with fresh humus from the compost or even new soil from the hardware store or garden supply store.

Check compost for slugs

slugs especially love the conditions in the compost and like to lay their eggs there between leaves or other waste. These can eventually get into the raised bed via the finished humus.

To find out whether the humus you want to fill into the raised bed contains slugs or slugs eggs, it is best to do a test planting in the spring.

That means you plant a few seedlings with the humus and wait a few days. If the young plants are quickly eaten away, you have probably carried slugs or slug eggs through the fresh humus into the raised bed.

Then it’s a matter of finding and removing slugs to do the actual planting. How to find the slugs in the raised bed, you read below in tip #8 (simply collect slugs ).

Use quality soil in the raised bed

Partially purchased soil from the tree species or garden specialty store may also contain slugs eggs.

However, this is usually only the case with very cheap products, because important production steps (such as sifting or the hot rotting phase) are often omitted in order to save manufacturing costs.

But if you buy a good quality soil (like this one from Hochwald*) from a specialized dealer, and preferably in organic quality, this should not be the case. Then you can be sure that no slug eggs are contained and therefore no slugs get into your raised bed.

4 Scanning young plants for slugs

Besides the soil, young plants can also be the trigger for a slug infestation in the raised bed.

In particular, this is often due to the press bales in which the plants were raised. The press bales are also a popular hiding place for small slugs or a popular place to lay slug eggs.

So it is best to check the bales for small eggs or slugs before you put them in the raised bed. This is a simple way to prevent slugs in the raised bed.

5 slugs defense with the right herbs in the raised bed

If slugs do show up in your raised bed with a lot of staying power, you can deter them with the right planting.

Namely, slugs don’t like certain smells and herbs at all and stay away from them.

slugs particularly dislike garlic, onions, savory, chamomile, lavender, rosemary and thyme.

So if you plant a row of these herbs or vegetables (or a mixture of them) around the edge of the raised bed, the smells should keep the slugs from advancing further.

Be careful with basil, though! Slugs love basil and are attracted to it, so rather than plant basil in the raised bed, plant it separately in a tub/pot or in a greenhouse.

6 Provide dry areas in the raised bed

slugs can of course move best on wet or moist surfaces, but even more difficult on dry ones.

That’s why you should pay attention to two things:

Make sure there is enough air circulating on your raised bed.

That is, you should make sure that the plants are not placed too close together, so that the areas between the individual plants can always dry out well, because slugs do not make good progress on dry surfaces.

It is best to water the raised bed only every few days, but then sufficiently.

Watering your raised bed only every few days has several advantages. On the one hand you reduce the water consumption, because less water simply evaporates.

Secondly, you ensure that the surface of the raised bed can dry again and again and is not constantly damp and provides ideal conditions for slugs .

If you want to know more about the total water consumption of your garden or if you want to calculate it exactly, just have a look here.

7 Remove weeds regularly

There is another simple tip to fight slugs in the raised bed or to keep them away.

And that is that you should make sure that you always remove weeds directly. On the one hand, weeds create shady or less well-ventilated areas, which in turn remain moist longer and are therefore better for slugs. On the other hand, weeds provide protection for slugs.

So if you regularly remove weeds from your raised bed, this is also a simple, but nevertheless preventive measure that helps against slugs in the raised bed.

Fighting slugs in the raised bed: tips with quick effect.
Now that we’ve looked at 7 really simple but effective tips for keeping slugs out of your raised bed, let’s move on to three more tips for immediately combating the slimy critters.

8 Simply collect slugs

Classically, the first thing I can advise is to simply collect the slugs even in the raised bed.

It is best to go out into the garden in the morning and hunt for slugs in the raised bed, because they usually come out of hiding at night (when it is wetter than during the day) and help themselves to lettuce and the like.

We also know that slugs prefer to retreat to dark, damp places, for example under plants, dead wood or other objects that provide protection.

In order to collect as many or as many slugs as possible in your raised bed, you can simply spread small boards in the raised bed the night before. It is highly probable that the slugs will seek out the boards as a shelter and settle under them.

When you go for a walk the next morning, you can simply turn the boards over and have an easy time collecting the slugs.

But what to do with the collected slugs ?

If you have chickens or ducks, slugs can serve as a successful snack. If not, the gentlest way is to release the slugs far away from the garden, for example in a meadow or field.

9 Scatter unpopular/insurmountable materials.

Now we come to the last, but still very helpful and immediately effective tip against slugs in raised beds.

And that is to scatter materials around your plantlets or bed that slugs don’t like.

Probably the simplest option is crushed eggshells. As you might imagine, crushed eggshells can be a very painful or insurmountable obstacle for slugs (probably similar to stepping on some Lego bricks barefoot – which has probably happened to all of us at some point 😉 ).
That’s right, so not only can eggshells be used as a great fertilizer (if you want to know more about that, just read on here), but you can easily place small circles of crushed eggshells around your plants to easily keep slugs away.

The next alternative for keeping slugs away from your raised bed plants is sawdust. Similar to crushed eggshells, you can sprinkle sawdust either around individual plants or around the entire bed.
It’s best to pile up a small rampart so that the slugs actually can’t get through. Because with their slimy underside they cannot overcome the dry sawdust. The disadvantage here is that after rain you have to renew the protective wall of sawdust.

A third option is to spread lime, again either around the individual plants or around the entire bed. This will also keep slugs away from the vegetable plants in your raised bed with immediate effect.
Since lime is very dry and also alkaline, slugs would lose a lot of moisture crossing over and their undersides would eventually be injured. That’s why slugs avoid crawling over lime.
Similar to sawdust, the lime track also needs to be renewed after rain.
Besides repelling slugs, you can also use lime as a fertilizer for your compost. You can find out how to do that here.

Last but not least, there is another home remedy for driving slugs out of your raised bed: coffee or coffee grounds.
Similar to eggshells, coffee can be used as fertilizer in the garden, as described earlier in this article. But slug repellent works just as well. To do this, you can either use coffee grounds to create a small protective wall or trail around your plants, or water them with irrigation water in which you have dissolved the coffee grounds.
Since slugs do not like coffee or the smell and taste, they will give your plants in the raised bed a wide berth.