20. July 2019

Guest blog: Maria's sourdough slug repellent!

This is my first time hearing about this method, but it actually works really well! Read more about Maria's sourdough slug repellent here.

En köksträdgård med täckodlade bäddar. Sourdough slug repellent, mulched beds.

Maria's kitchen garden has a nice view of the fjord in Molde.



I did a lecture in the Norwegian town Molde, where I met the garden blogger Maria Berg Hestad. I thought I had heard it all by now, but she told me about her unusual method of getting rid of slugs – with sourdough! Maria was finally able to write a guest blog about hunting slugs here at Sara's Kitchen Garden. Enjoy!


Molde is known as one of the most slug-rich areas in Norway. The Spanish slugs got here already in the eighties, and they have been enjoying our mild coastal climate ever since. I could pick probably a hundred slugs on a 10 square foot area when we bought our house in 2010. Right in the same spot where my kitchen garden is located now.

I almost gave up on my gardening dreams, but I actually started to notice fewer and fewer slugs the larger my kitchen garden grew. It's hard to pinpoint what exactly made this change possible, it could be sheer willpower for all I know. I just had to take up the fight against the slugs!

Fast-forward to a few years after I started the garden, the slugs are under control and I learned to live with the ones that stick around. So, my best tip for anyone who wants to deal with the slugs in their garden is to simply start a kitchen garden. This will give you even more motivation to act quickly, which has worked really well for me.


En köksträdgård med täckodlade bäddar i en slänt. Sourdough slug repellent, mulched beds

Maria wants to mulch the garden, despite all the slugs. She kills the ones that don't get stuck in the sourdough slug repellent trap by squeezing them to death.


Dealing with the slugs

I sporadically use both nemaslug and ferramol (nematodes and slug pellets.) These two have helped me so much when things were really bad. There are only a few spots in my garden where the slugs can hide, so nematodes and ferramol might not be the best option. That's why I only use it routinely in the most overgrown parts of the garden and not primarily in my kitchen garden.

The most important part of my fight against the slugs is to immediately take out every single one I come across. It's very effective! I eliminate them in the simplest way possible, I simply squeeze them to death. The small ones can be killed using my fingers only. The principle is to use as little time as possible on each slug. If I find a lot of them, I simply put them on a flat stone and crush them with a shoe or a rock. I want to get rid of the slugs as soon as I can to get on with the more enjoyable tasks in the garden.

This way, the fight against the slugs becomes a natural part of the gardening routine instead of seeing it as a huge effort that takes up a specific time window every week. We just need to get used to dealing with the slugs. Everybody thinks they are disgusting at first, but you get used to it after a while.


En hink med surdeg gömd under en tomatplanta. Sourdough slug repellent, a bucket hidden under a tomato plant.

A bucket filled with sourdough placed between the vegetables in the greenhouse. Maria fills it up with slugs that she finds in the garden.


Sourdough slug repellent

So, what about the sourdough slug repellent then? Well, I don't actually like buying these expensive and fancy special treatments. I want to use what I have at home instead. That's how I discovered that sourdough seems to have an effect on the slugs.

The original plan was to see if the sourdough could lure the slugs into a trap, but it turns out that the slugs actually die when they end up in a bowl of sourdough. It seems that they either drown or eat themselves to death, I'm not sure which. I know that slugs don't drown in water (or beer for that matter). They simply sink and crawl along the bottom of the container, and get out of the water again. They can apparently hold their breath for a really long time! But they don't sink in the sourdough, they simply float in the upper layer until they die shortly after. Then they sink to the bottom.


Sourdough traps in my greenhouse

I grow a lot of leafy greens in my greenhouse in early spring, and I would like to avoid harvesting a bunch of slugs with my vegetables. Early in the season, the slugs are so small that it's difficult to squeeze or cut them. That's when I usually just gather a number of slugs and throw them into the sourdough trap. Plenty of them are attracted to the sweet smell and crawl into the bowl themselves though. The sourdough slug repellent is apparently a very good alternative to beer traps!

The sourdough actually lasts for quite some time, up to three weeks. As long as it doesn't dry out, that is. It doesn't smell bad, even though the bowl is in my warm greenhouse and full of slugs by now. It just smells like sourdough.


En fin köksträdgård i en slänt. Sourdough slug repellent, the kitchen garden.

The garden produces plenty of vegetables all year round, despite the slugs! I hope this will inspire all of us who want to grow our own food. The sourdough slug repellent really works!


Make your own sourdough

I don't really have any preferences when it comes to what kind of sourdough you should use. Grab whatever you have available or make a new one. The taste doesn't matter! It should, however, be thick and smell. The consistency should be like runny porridge. It will start to separate after a while though, with the water on top and the dead slugs sinking to the bottom. But the sourdough slug repellent is still effective. When the sourdough is full of slugs, you can bury the dough and the slugs together with bokashi in your garden.

I use a lidless jar to catch the slugs in my greenhouse, but I try to only use traps that no other animals can fall into in my kitchen garden. For example a milk carton.

The slugs tend to change their eating habits as the season goes on. They eat different vegetables in different locations. This is the perfect time to try new ways to catch them. So, why not try using my sourdough slug repellent? It works really well!
/Maria Berg Hestad


Porträtt av Maria Berg Hestad


More Garden DIY from Sara's Kitchen Garden: Making a woven compost basket


About Maria

Maria Berg Hestad grows her vegetables in Molde in west Norway. The garden is around 3200 square feet large and is located next to Maria's house with a beautiful view of the fjord. Maria's family consists of two grown-ups and three children, and they are self-sufficient from June to December.

Follow Maria here (in Norwegian):
Facebook: Det grønne skafferi 
Blogg: Det grønne skafferi 
Instagram: Det grønne skafferi 


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