All photos © Craig Mackintosh
This is not your usual drinking establishment. There’s no music, no dancing, no lights — not even any discussion. And, as the title of this article suggests, all the guests are — as is sometimes the case in drinking establishments — rather slippery characters. But, despite the general dinginess of the place, there are often even queues to get in!
In this article I want to share some successes with slug beer traps, and tell you how you can easily make a very effective trap — by simply repurposing the plastic 1.5 or 2 litre drink bottles that are always too easy to find.
First, a little essential background on slugs and snails
Slugs and snails can be a nightmare for gardeners, particularly those who live in wetter areas, and areas without a lot of sunshine (snails have shells to retreat into to when it’s sunny — whereas slugs must ‘run’ for cover). Temperate climates, particularly cloudy ones like the UK, are particularly prone to infestations, but they can be a problem in many regions of the world. Gardening enthusiasm can quickly dissipate upon early morning discovery of new plants and seedlings that have been lovingly planted just to be devoured overnight. Oftentimes vulnerable young seedlings can be damaged beyond viability, or completely consumed down to ground level. You want to increase your self-resilience, and so it’s tempting to think of these mollusks as public enemy number one.
But, like pretty much everything in nature, these creatures play a valuable role in the ecosystem — breaking down decaying material and recycling it back into the soil. Slugs and snails will feed on almost anything digestible, including living and decomposing plant matter, paper and cardboard, the carcasses of animals, like mice, etc. As such, it is, I believe, better to address slug/snail population ‘imbalances’ (i.e. excess populations), rather than to seek to completely eliminate them (a virtually impossible task).
Understanding a little about a creature’s life cycle is valuable for knowing how to manage it. Slugs and snails reproduce by laying clusters of little white eggs in hideaways in your garden — like in a cold compost pile, damp cracks in your soil, under bits of discarded wood and other debris, and so on. Sometimes eggs are unwittingly imported into your garden via off-site soil, manure, and even purchased potted plants, that you’ve brought in.
Slugs and snails, depending on which varieties you have, can live from one to five years, and some can take up to two years to reach maturity. This is good news for gardeners, as the relatively long life cycle means that once you manage to implement a successful system of control, then it will take longer for them to bounce back to another out-of-control population density. Additionally, the older and larger the slugs and snails get, the more voracious and destructive they can be. ‘Baby’ slugs and snails are not nearly so damaging as their older peers. This, once again, translates to good news, assuming you can incorporate a decent method of control.
I live in a cold temperate climate in central Europe. I’ve seen Winters here get as low as -27°C. The disadvantage of this climate is the relatively short growing season, but it comes with benefits also — that being that many creatures which could otherwise get out of balance are killed off by several months of frigid temperatures. Slug and snail eggs that have not been laid deep enough will often not survive the Winter, and those that do survive are slower to rebound in the Spring.
As many of our readers will be aware, an ideal solution to dealing with any ‘pest’ is to incorporate a natural predator in your garden design. In the case of slugs and snails, ducks are excellent ‘vacuum cleaners’ for them. You can read more about this here and here. Most people with ducks don’t have much of an issue with slugs and snails, and the beauty of controlling them in this way is that you also get a return — in duck eggs and meat (if you’re that way inclined). The problem becomes a resource — the slug/snail-duck relationship becomes a natural cycle that requires little input from yourself, and generates benefits beyond just mollusk consumption (i.e. duck fertiliser, entertainment and companionship, and more). But, what if you’re not yet in a position to suitably house and care for ducks?
Enter: the slug pub!
The slug pub
Slugs and snails are attracted to the smell of yeast. Burying small bowls/jars/tins in the garden — sufficiently so that the rim of the container is at ground level — and then filling with beer, is a well-recognised and simple way to attract and drown slugs and snails. In the picture above, you’ll see another method — one that is very easy to make, and comes with a couple of bonus ‘features’.
Take a 1.5 or 2 litre plastic ‘soda’ bottle, and cut a three-sided rectangular ‘door’ in one side. This door will be folded down to become a slug ramp, or ‘highway’. You want to ensure the door is about 8 or 10cms long, and that the bottom of it is about 5-7cms from the very bottom of the bottle. Then turn the bottle over, and repeat the process on the opposite side.
Then, fold each door down, crimping it firmly with your fingers to ensure they remain relatively flat/horizontal.
Now all you need to do is make a small hole in the soil of your garden, between a couple of your vulnerable plants, and bury the bottle sufficiently so that the ‘ramps’ are at ground level. You can place a little soil along the outward edge of the ramps, to ensure they stay firmly down, for easy slug/snail access.
Then, fill the bottom of the bottle with the cheapest, nastiest beer you can find.
A slug pub in place — complete with overnight guests.
The additional benefits of using a bottle like this, as opposed to the traditional method of burying a bowl or jar, are that when it rains (remembering that slug/snail-prone regions are usually wetter places) the beer doesn’t get diluted so easily — which would make the trap less attractive and effective — and soil and other garden debris is less likely to end up in the trap (debris like straw mulch, if it finds its way into the trap, can become an escape route for the critters to climb back out again).
One more bonus is that emptying the bottle is mess-free — you can pick it up by the clean neck of the bottle, and not have to handle the slimy rim of other kinds of containers. (Slug slime is not easy to get off your hands!)
My experience with the slug pub
As mentioned further above, Winters here can get extraordinarily cold. But, our climate is changing…. Our last Winter was almost a non-event — we kept waiting for Winter to arrive, and then it was Spring…. This was followed by a particularly wet, cloudy and dismal Spring, which was in turn followed by the current ‘Summer’, which brought — over the last six or so weeks of June and July — an almost daily occurrence of thunder and lightning storms (our house was struck last week!), with their associated heavy downpours. These are the kind of storms you normally may see for only a few muggy/humid days at the end of Summer here. This topsy-turvy weather has translated into a slug resurgence of horrific proportions. I’ve spoken to older folk in the area who described this year’s slug problems as something they’ve never witnessed in their long, gardening lifetimes. My wife and I watched with some feeling of despair in Spring as our work became a cycle of diminishing returns as an army of slugs (snails are not a problem for us) devoured much of what we’d planted…. I thus got to work, putting out about twenty of the traps above.
The result? The morning after initial installation, I found from 20 to 40 slugs — and in some cases up to 50 — in most of the traps. This was encouraging, particularly when you realise that each slug caught means one less slug to reproduce by laying eggs! This kind of cull count, albeit a little less each time, continued for a couple of weeks — counted when changing the beer every two or three days (nobody likes stale beer, and slugs are no exception). Over the ensuing weeks we ‘harvested’ less and less as the slug population started to get under control. As you can see, slugs in this part of the world are definitely not teetotalers — in a six-week period I estimate that well over 2000 slugs imbibed themselves to a happy demise.
Practical and philosophical aspects
Killing creatures is not something I take lightly, and we must also consider the wider environmental impact of our methods. Again, ducks would be preferable in this situation, but beer traps still stack up pretty well as a stop-gap measure until you can position yourself to take on a waddling of ducks. The trap itself can be repurposed from discarded bottles, and in many places you can find very inexpensive locally made beer (as is the case here). Some people also find they can substitute beer with a mix of yeast, honey and warm water — warm so as to encourage the yeast bacteria to multiply. (I haven’t personally tried this as yet, just because the sheer numbers of slugs we had to deal with led me to want the alcohol content to ensure they don’t survive their liquid lunch. If we wanted to harvest anything this year, we couldn’t afford to experiment too much!)
And, with the slug pub you can simply dump the dead slugs into your compost pile, so the nutrients they took from your garden go straight back into it again. (Since these are ‘marinated’ slugs, some might even find a culinary use for them? Slug Shish Kabobs, anyone? Sorry — just kidding, I wouldn’t recommend this at all….)
Some may wonder if other, more beneficial insects and creatures are killed by the traps. Your experience may vary, depending on your own local fauna, but in my garden I’ve found only the very occasional beetle or spider — certainly much less than 1% of the overall slug kill rate. It seems that slugs are far more inclined to rush to the pub than other creatures. I think the very few non-target bugs that I did find probably fell in, rather than having been lured in by the scent.
And, finally, I console myself with a couple of thoughts: 1) I’m putting the beer out, but I’m not forcing the slugs to imbibe!, and 2) the slugs depart this mortal coil in a rather merry state….
It’s important to recognise other weaknesses in the garden system that can encourage slugs. Purchased seedlings normally come in small pots with rather ‘sterile’ soil. For most nurseries, providing you with seedlings in a microbially rich soil environment is not priority. The plant only has to ‘look good’ at point of sale — its subsequent performance is your problem. As such, most of the seedlings you can buy are not rich in pest-repelling vitality (to understand these points better, read this, this and this), and thus their poor state of health can make them even more attractive to slugs and snails (and certain insects…) than they otherwise might. Assuming the plants survive initial planting and establishment, their health can improve as the seedlings’ roots move out into your garden soil, with (hopefully) its better microbial environment.
Small seedlings and freshly germinated plants also haven’t yet developed the tougher skin (epidermis) on stalks, branches and leaves that you see developing later. Infant plants are much more ‘succulent’ and easy to bite into. As such, Springtime is the period that is key to getting your slug/snail population under control, and having previously created your own ‘biovital’ soil mediums for seedlings should help also. (I don’t have a greenhouse yet, and so, along with our short growing season, I haven’t been able to develop a full seed-to-harvest process to date.)
As mentioned further above, garden debris like wood, etc., can become habitat and egg-laying grounds for slugs and snails. I recently discovered a couple of nice, plump hedgehogs in the dark and secluded rear corner of the yard, and so put some extra bits of wood and straw there, as hedgehog habitat, to encourage them to stay. Hedgehogs eat slugs — not in the quantities a duck will, but they certainly help clean up slugs in the isolated areas of your garden that you may not otherwise attend to. On a recent moonlit night I was rewarded with the sight of one of these prickly guys walking the length of one of the raised beds. I like to think of them patrolling as I sleep.
It is my expectation that with a little — even slightly lazy — vigilance for the remainder of this year, in replenishing these traps, the slug population will continue to shrink. Now, in early August, I’m replenishing the traps about once per week or so, and find only about five or ten slugs in each. This translates to less eggs being laid — and so I expect that next Spring will have our slug levels in a far more manageable state. I also expect that this year we will have removed most of the larger, more mature and mobile slugs, leaving us with smaller, far less destructive ones.
And who knows — perhaps we’ll have a decent Winter this year?
Bonus photo: We have other creatures in our garden, like our daughter, who loves the time we
spend in it. As Geoff Lawton wrote me about this photo — "If she knows how to compost,
she’ll be a survivor."