Mechanical protection against garden slugs?

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FBeyer
Posts: 1075
Joined: Tue Oct 27, 2015 3:25 am

Mechanical protection against garden slugs?

Post by FBeyer »

So my fledgling square meter garden is coming along nicely.

That is, it WAS coming along nicely until a large amount of slugs decided that all our small seedlings (yes we started a garden way too late, that was actually somewhat calculated) make for a great buffet.

Naturally I've built a couple of beer traps out of screw cap milk cartons and beer and I've manually decapitated something like 30 slugs the last couple of days, but what I want is not to turn the furthest corner of my yard into an execution ground, I'd much rather find some mechanical way of keeping slugs away.

Are any of you aware of good solutions that might take some work up front, but very little maintenance afterwards? I'd like to protect the garden in a bed-wise manner rather than plant-wise so pouring coffee grounds around all the plants is less preferable to proofing the entire frame.

The things I've thought about so far include making a rope of out brambles and tying it around the base of the raised beds in the hopes that slugs don't want to cross a barrier like that. Or building a sloping board on top of the bed frames hopefully because the slugs can't crawl head first across a downward sloping barrier.

There are three raised beds and they are all 1.4 meters square.

Any experience with ecologically slug proofing your raised beds?

wizards
Posts: 121
Joined: Sun Mar 31, 2013 8:24 pm
Location: Denmark

Re: Mechanical protection against garden slugs?

Post by wizards »

Buy or build something like this?:

https://www.landhave.dk/produkt/snegleh ... gKBsPD_BwE

We haven´t had slug problems, so can't guarantee it works...

vexed87
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Location: Yorkshire, UK

Re: Mechanical protection against garden slugs?

Post by vexed87 »

You are probably experiencing a population boom of slugs because you are creating a idyllic environment for them. This is one of the hallmark problems with monocultures raised beds, growing in rows, or simply too many of the same species in a cluster. Try space them out next time and work on the biodiversity.

Your next thoughts should be to encourage more insect biodiveristy, and hopefully your will attract more natural predators of slugs, all you have to do is make this environment idyllic for them also. They already have the food source (slugs in abundance) so something else must not be quite right. In the UK, we have hedgehogs, toads, several birds etc. Hedgehogs for instance can't get into most walled off gardens unless it's made easy (hole in the fence!) Toads, and other pond life won't be nearby unless there's a pond, or water source. Your options will depend on your local ecology. These might be helpful reading: https://www.rhs.org.uk/advice/profile?pid=228#section-3, https://www.rhs.org.uk/science/conserva ... our-garden

Failing that, strategic placement of Diamatecous Earth. It is organic and non-toxic, sadly though, it's indiscriminate and kills beneficial bugs too. I have been known to surround my seedlings with it, so they had a chance to establish, then slugs are less of a concern. It does wash away after a period of rain, so isn't a permanent solution/problem.

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Sclass
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Location: Orange County, CA

Re: Mechanical protection against garden slugs?

Post by Sclass »

I haven't tried this, but look into copper barriers. My lab mate in school used to collect up all the surplus copper seals from the high vacuum people and place them around his veggie garden. He said it kept snails out. Never gave it much thought till now.

A quick search on YouTube shows some people experimenting with copper tape and it seems to deter snails.

7Wannabe5
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Re: Mechanical protection against garden slugs?

Post by 7Wannabe5 »

I haven't had problem in my Midwestern gardens, but have heard tell that this is common with use of mulch cover in wetter regions. I agree with what Vexed87 wrote about making the problem its own solution being the perma-culture ideal. You could fatten up a duck on slugs, use them as fish bait, or cut right to the chase.

http://feralfood.blogspot.com/2009/12/f ... ho-is.html

George the original one
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Location: Wettest corner of Orygun

Re: Mechanical protection against garden slugs?

Post by George the original one »

Beach sand is said to interfere with their slime trails such that they can't glide across a substantial sand barrier. Never tried it, but you certainly don't see slugs on the beach, LOL!

Eureka
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Re: Mechanical protection against garden slugs?

Post by Eureka »

vexed87 wrote:
Mon Jul 24, 2017 6:13 am
You are probably experiencing a population boom of slugs because you are creating a idyllic environment for them.
@vexed87
Don't blame us. We didn't create any idyllic environment for a new invasive species of slugs in our part of the world. Climate change did. And for your record, they are all over the place here where I live, also in my next door nature reserve with zero mono culture and zero human grown nutritious-high veggies and lots of hedgehogs, toads and insects. When you hike the trails, you really have to make an effort not to step on them.

@fbeyer, apparently you should leave the leopard slugs alive as they are a natural predator: https://www.sneglebekaempelse.dk/leopardsnegl/

ducknalddon
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Re: Mechanical protection against garden slugs?

Post by ducknalddon »

You probably want something gritty like crushed egg shells or ash to act as a barrier.

BadHorse
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Re: Mechanical protection against garden slugs?

Post by BadHorse »

Ah, the infamous "killer slugs", bane of garden beds and ecosystems alike.

These were the main reason I gave up on gardening, after realizing that 90% of the time is spent violently killing things, not tenderly nurturing little seedlings. So much for meditative hobbies.
Like @Eureka said, they are an invasive species with few natural enemies. They are even more abundant in natural environments (which tend to be more overgrown and humid) than in cultivated gardens. Aside from feasting on plants, they will also kill and eat earthworms and other slugs.

If I were to start gardening again, I'd probably go the route of sloped fencing around each garden bed. If DIY'ing, make sure to get the angle right. I also toyed with the idea of wrapping the copper from old cables around the garden beds, but don't know if it would actually work.
Some breeds of duck will eat the grown slugs, and chicken will eat slug eggs and very small slugs.

Alternatively, stick to the plants they don't favor. iirc onions, leeks, and carrots were off their menu. They love cabbages, and have an especially infuriating trick with squash and pumpkin: They leave the green plants and the petals alone, but will crawl in and eat out just the center of each flower after pollination. Maddening. I got less than one fruit per plant, despite ample flowering and twice-daily slug hunts.

FBeyer
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Re: Mechanical protection against garden slugs?

Post by FBeyer »

I think I will try to go for sand, for two reasons: first to protect against slugs... duh! Second because my hand mower doesn't mow completely flush with the raised bed and so I either need to find a manual way to trim that last strip of grass or I need to find a way to stop grass from growing so close to the edge of the beds. Sand is cheap, easy to work with, doesn't require maintenance and should fix two problems in one go.

Of course we're going for something that is not as mono cultural as one of our beds is currently (16 squares of broccoli... wtf) but our beds are generally pretty mixed with regards to composition. Some of the neighbours don't take take of their back yards so there are very good living spaces for slugs in certain spots close to my house. I went on a garden trowel rampage yesterday and killed almost 50 slugs[1]... So yeah, as BadHorse said: This is very much more about killing animals than nurturing life at the moment.

I've found an alternative to the aluminum profile angled tops which used a soft plastic overhang instead of a solid 'roof' to cover the bed. The slugs can climb up the side of the bed, but they can't climb upside down on the small plastic sheet. If sand doesn't work I will have to look into whether that plastic sheet solution works just as well as an aluminum profile.

Also: I'd LOVE to have chickens and a hedgehog in my backyard but there aren't a lot of hedgehogs here. Not as far as I know. My garden IS raised above the ground so I'm certain I could build a very nice shelter for a 'hog there. Then I'd just need to transplant one into my garden and it'd be by new second-most favorite pet, right after the eisenia foetida.


Thanks peeps! Much appreciated.


[1] I haven't killed this many animals since I worked with animal testing in cancer research...

FBeyer
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Re: Mechanical protection against garden slugs?

Post by FBeyer »

ducknalddon wrote:
Tue Jul 25, 2017 2:08 am
You probably want something gritty like crushed egg shells or ash to act as a barrier.
That could be an idea too. Save shells from cooking and save the ashes from the bbq?

IlliniDave
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Re: Mechanical protection against garden slugs?

Post by IlliniDave »

Mulch with a lot of coarse pieces is heaven for slugs and snails. They are relatively nocturnal and need somewhere cool and damp out of the sunlight to spend their days. Its also where they lay their eggs. Drip irrigation helps versus broadcast irrigation. Crushed egg shells make a barrier around plants. Seedlings/transplants are especially vulnerable. Beer traps work really well - I use plastic picnic plates with some depth (~1/2 in) to them and scoop out an area so the lip of the plate is at ground level. Fresh beer every evening. It will take some time to get a large population under control. Copper has been mentioned and I've heard it works but never tried it myself. A moat of table salt will work by killing any that crawl over it, but that's tough to do in a garden. I've used it on the inside of my house to good effect when they found a way to follow pipes/wires indoors until I located/sealed the entrance they used on the exterior.

I've noticed they prefer weak/damaged plants/leaves, and that along with their attraction to beer and mulch makes me suspect they are attuned to detect fermentation and similar vegetative decomp processes. It's probably best to minimize that sort of material in the area during the growing season.

The biggest long-term improvement for me was forgoing heavy surface mulching. Without it populations are much less apt to explode. My family growing up were all gardeners and they never complained about excessive slug problems but they only mulched in the fall and then turned the mulch down into the soil in spring, leaving a bare dirt surface for planting.

vexed87
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Location: Yorkshire, UK

Re: Mechanical protection against garden slugs?

Post by vexed87 »

Eureka wrote:
Mon Jul 24, 2017 5:03 pm
@vexed87
Don't blame us. We didn't create any idyllic environment for a new invasive species of slugs in our part of the world. Climate change did. And for your record, they are all over the place here where I live, also in my next door nature reserve with zero mono culture and zero human grown nutritious-high veggies and lots of hedgehogs, toads and insects. When you hike the trails, you really have to make an effort not to step on them.
Hah, well that sucks! But I wasn't talking about climate change, although that may play a part in introducing them to your neck of the woods. What I meant is that planting lovely tender seedlings in high concentrations in easily accessible areas of the garden is asking for trouble! The slugs will go into frenzy, something which is much harder to achieve for slow moving pests if your garden resembles a open meadow and your edible plants are dispersed over a greater area. This is a major drawback of planting lots of seedlings in raised beds, the concentration of food supports larger numbers of slugs in the same area, and slugs will have not to make a perilous journey from one plant to the next, in a raised bed, it's almost effortless. Yes, predators will come in sufficient numbers eventually, but perhaps too late for the seedlings in the midst of a frenzy!

@Fbeyer, mulching is supposed to attract more slugs in temperate climes (you are in temperate climate, right? It's important because the advice is highly dependent on your location). All the rotting material in a damp area will provide an ideal hiding place for slugs, their offspring and eggs, keeping them safer from predators, but as it rots it's also ideal food source for slugs, it could contribute to a boom in numbers in temperate areas. Much better to apply mulch at the end of the season while you are not growing seedlings, or only apply fully-rotted compost.

You might have better luck if you can plant your seedlings between already established species that don't attracts slugs, the foilage of the more mature plants can act as a physical barrier, or distraction. I'm not sure which is actually happening, but I have noticed that seedlings amongst other established plants are less prone to slug induced doom. In my experience slugs are usually only a major issue when your seedlings are small and tender, for instance they can't keep up with the growth of my established marrow plants, despite how many are nibbling. Possibly consider starting vulnerable seedlings indoors/greenhouses and later transplanting them outside so there's less chance of them being eaten early on.

IllinDave is also correct in his observations that they will tend to go for the sick/diseased plants first. So there may be soil nutrient deficiencies to address, did you do soil tests to determine what does well where before planting? Sickly seedlings are also less likely to bounce back from an attack.

FYI, 1 slug can lay 300 eggs. So Nematoads are another great organic option because they destroy slugs through all stages of their lifecycle, including their eggs (future attackers!) but covering an entire plot with the treatment is probably impractical... probably best reserved to pests confined to smaller spaces.

Zeran
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Re: Mechanical protection against garden slugs?

Post by Zeran »

In the endless battles between slugs, my greatest ally has been cold winters and hedgehogs.

A method of protecting your plants is to grow onions and garlic & leeks around the borders, slugs don't like this.
I also place out crushed egg shells, sometimes coffee grounds and very occasionally a ring of salt.
You can place your waste leek-ends around the border as well.

If hedgehogs are a possibility in your garden, a pile of sticks makes a suitable home for them.

Slugs are going to be a serious problem for me in the future, the winters are getting warmer, and now rarely getting below freezing in the UK, so the slug numbers are increasing every year.

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