How to Get Rid of Slugs In A Terrarium

This post may contain affiliate links. Read the full disclosure here.

I honestly had no idea how much of a problem slugs could be in a terrarium until it happened. It doesn’t help that we have a lot of creatures – isopods, geckos, a frog, miscellaneous others – that we don’t want to harm.

My only option was to pick out the slugs one by one, but it was weirdly effective!

You can buy slug pellets that aren’t horrific for the environment, BUT I didn’t find the explanation of how they worked sufficient enough for me to risk the rest of the gang. I wanted to target slugs specifically, dispatch them in a kind(ish) way, and not pose any threat to any of the other animals.

pretend it’s a fenestration

What do slugs eat in a terrarium?


Slugs will have a go at most green things. Mine really, really liked my Calathea and ferns. They weren’t as fussed by plants that have calcium oxalate crystals in their leaves but I’m pretty sure they’d have a go at them if there were no other options.

All my terrarium Calathea had loads of little bite marks out of them. They just ate the ferns – no holes – just the whole freaking leaf.

They do like to eat new growth – even if the plant is toxic. I’m gonna guess that the volume of calcium oxalate crystals increases as the leaf ages.

This aglaonema has barely any bite marks out of the older leave, but the younger ones are fair game:

Annoyingly, NOTHING eats slugs, bar one animal. Even animals that traditionally eat slugs, like hedgehogs, won’t eat them unless there’s no other option. Slugs contain toxins, so they’re not an ideal meal for 99.9% of animals.

Even chickens aren’t too fussed, and chickens are NOT fussy.

The only animals that will happily eat slugs are ducks.

The idea of a pet duck is lovely, but as someone who fostered a duckling until a rescue could take it, let me tell you – they are messy. They poop everywhere, almost constantly, and they have no issue with spreading it around anywhere and everywhere. Luckily, the cuteness makes it worth it, but also….my way of getting rid of slugs is *slightly* less gross.

Are slugs bad in a terrarium?

They’re not that bad. We had literally hundreds and they do do damage to plants, but they don’t kill them.

The issue is that it’s basically impossible to not get them, as the eggs tend to come in on the leaves of plants, and they reproduce quickly if you keep a close eye on them.

They do tend to have a preferred plant – in my case Calathea Velvet Touch:

To be honest this is probably my fault – the plant was way too big to be in the terrarium so I had to cut her back frequently. All new growth was immediately set upon, so it never really had a chance. I’m surprised a Calathea can be so tenacious.

How to get rid of slugs in a terrarium

I have tried everything. Any kind of trap just collected isopods and springtails. I didn’t trust chemicals to target only slugs.

So I picked out every one by hand.

It actually only took a week or so of dedicated slug removal to get rid of 95% of the slugs. They seem to have a hierarchy, so spend the time removing all the ones you can see. Then wait a day or so, and numbers will see to jump up again. Pick them out.

I think they’re a bit like chickens – some of them aren’t allowed out until the top brass slugs have had their fill of Calathea.

I recommend keeping a roll of kitchen roll/paper towels next to the terrarium so you’re always ready to grab them.

Once you’ve got rid of the popular kids, you need to up your game with a bit of bait – I like a big chunk of cucumber – remove the skin to make it more appealing OR cut in half lengthways so there’s more exposed flesh. As it were.

The slugs will flock to it. Very slowly. So not really flock. But they’ll get there eventually.

Lettuce is also a good shout, because you can fit a lot of slugs on it. This is perhaps better for the squeamish because you can just pick up the vegetable and throw the whole thing away.

Slugs like the damp and the dark, so to maximise your haul, spray your terrarium down around 8pm. At midnight, a frightening amount of slugs will appear, considering you removed dozens and couldn’t see any more.

After about two weeks of continuously pulling out slugs, they’d mostly gone.

So what do you do with the slugs?

Ok, I’m not proud of this, but I couldn’t kill them myself, but nor did I want to release them into my garden. So I just put them in the bin. We don’t have a separate food waste bin so there was plenty for them to eat. If there’s a massive slug infestation at a UK landfill I’m sure that’s a coincidence.

I should have saved them up in a box and gone to feed the ducks. Potentially scar a few toddlers with my box of slugs.

Caroline Cocker

Caroline is the founder and writer (and plant keeper) of Planet Houseplant

Leave a comment