/ Home & Energy

Is it possible to hold back the slugs?

Slugs – a gardener’s worst enemy. There are a number of methods out there to stop them in their tracks, be it environmentally friendly or chemical, but have you ever found one that does the trick?

Ask any gardener what their worst pest is and slugs and snails will feature high on the list. Three quarters of Which? Gardening members told us that they’re a real problem.

The tell-tale slime trails across your decimated plants, the stump-like remains of your seedlings and the gaping holes in your hosta leaves all show that slugs and snails have been busy eating your carefully tended garden. The damage is enough to make you hop round the garden in fury.

Barriers to protect your crops

In an attempt to get rid of slugs and snails gardeners use barriers, pellets and nematodes with abandon. But is it time to throw in the towel and make peace with these pests?

Our recent tests showed that environmentally friendly barrier methods are not much better than leaving your plants unprotected, especially when you factor in the faff of installing the barriers.

We tested plastic barriers with sharp teeth that were supposed to deter snail, but the pests simply hurdled the obstacle by arching their bodies. Granules that were supposed to be too sharp to crawl over became soggy and sticky when watered. Copper is another deterrent but the tape we used was breached within days.

Some barriers showed promise, such as wool pellets that created a hairy mat, or a gel that made a slug turn through 180 degrees and head off in the opposite direction, but even these failed to protect our seedlings for long.

Home-made methods, such as egg shells, beer traps or coffee granules may be cheap alternatives, but our poll told us most members have had poor results. Ducks and geese were the best performers, although these have to take their place in the food chain and are often fall prey to foxes.

Biological and chemical controls

Then there’s Nematodes which seem to work well on slugs, but not on snails. These tiny parasitic worms are watered onto the soil and work their way into slugs where they infect them with a lethal fungus. But they’re a nuisance to buy and use as they have to be ordered online and then kept in the fridge until the weather and soil temperatures are right.

The problems with pellets containing metaldehyde are well known, such as causing harm to birds and pets if eaten in large quantities. It’s also known to pollute water when used in high doses in agriculture. Some experts even predict it may be banned in the UK if the problem is not controlled.

Ferric-phosphate pellets are certified as organic, but some research suggests that it may cause problems for earthworms and alter the chemical balance of the soil.

So it looks as though we have three choices: using remedies that may be less than environmentally friendly, carrying out night-time raids with a torch and bin bag or learn to live with slugs and snails. Which method do you use? Or do you have a secret tip that we’d all love to to know?

Comments

The best solution to slugs and snails in my experience has been to play host to a hedgehog. If your garden has a few sheltered areas it will find somewhere to sleep in very cold spells. Look after it during warm spells during winter when it is likely to forage for food: put out some cat food. Don’t discourage foxes – they eat slugs too!

Brian Cox says:
7 March 2015

Looking after hedgehogs is commendable anyway – they are in serious decline – but please make sure that the cat food doesn’t contain fish because it’s not good for their tums. Actually, I’ve heard that slugs and snails are not at the top of their wishlist, but I’ll tell you what – they adore the mealworms which we put out for the birds.

Margaret says:
8 March 2015

The problem with putting out cat food is that the surrounding cats are liable to gobble it 1st. Apparently hedgehogs love milk but I have heard it is harmful to them. I once gathered snails and dropped them into a deep container 1/4 filled with water. They all died but it needs emptying often or it absolutely stinks

I would love a resident hedgehog but I have not seen one for years – are they in decline?

Falkenna says:
8 March 2015

When I dropped snails into a deep container of water, they all crawled out long before they died! But I found that the beer cups work very well – except for the same problems you mention of frequent emptying and a horrific stink.

Dropping slugs into a pale of water is fine, so long as you introduce SALT . This will disolve the slugs – bit messy I admit, but they dont get out. I used a litter picker device (two years ago over a few days we collected some two hundred slugs using this method and some of the slugs were huge).

It appears so, bbookham…I do hope they make a swift return soon:

http://www.theguardian.com/environment/2013/jan/29/hedgehog-population-dramatic-decline

Thats good news on the fox front as we have quite a few travel through our garden. Overall though are preferred method is hunting with sharp pointy sticks rather than chemicals. Accepting that there is an acceptable damage rate is also helpful in being serene about the situation.

In the previous Conversation about slugs it was suggested that ferric phosphate was safe, and I had my doubts at the time. Most chemicals are not good at distinguishing between harmful and beneficial species. I’m glad that we have a biological control agent for slugs. One of the problems of biological control is that it can be too specific, which is why it works with slugs but not with snails. I would rather pick up snails than slugs, so I will give it a go.

When I was liitle our next door neighbour used to patrol his garden and despatched slugs with a pair of scissors. Others used to sprinkle them with table salt. I confess to protecting new seedlings planed in the garden with a minimum of slug pellets but, once established, give the slugs and snails (on chalk we have both) a free reign. Put enough plants in and you can get your fair share. Same with pigeons eating the peas and broad beans – share and share alike.

I also try to make up for my wicked ways by feeding the birds throughout the winter.

Malcolm – I think my nan still uses the scissors technique! I just used to pick the snails/slugs up and move them to another place in the garden, never thinking they’d squirm back to the same vegetable patch…

In the winter months I always go on slug patrol before I go to bed. I venture out into the dark with a torch and try to remove as many as I can. Problem is I can’t kill them, I just move them further away but they always make it back. My plants are no more 🙁

If slugs and snails only come out at night, perhaps you could stick solar-powered LED lights near vulnerable produce? Or might that create a slug rave – they might come from miles around?

A slug rave… O_O I’ve just pictured slugs with glow sticks and neon paint… Ah look, there’s actual neon sea slugs 😮 :

http://en.wikipedia.org/wiki/Nembrotha_kubaryana

If these were on the loose in your garden, Andrew, I’d stay off the night patrols!

Thrushes like snails and possibly slugs. Perhaps put effigies of these around the garden as scareslugs? On the other hand we could just come to an amicable agreement as I do with bullfinches that feast on the buds on my cherry tree – give them bird seed so they like me and maybe the cherry tree will have enough blossom left to cheer up a few Spring days soon.

They look harmless and slightly “pet-worthy”..Malcolm – Haha. Great tips, so far, from yourself and wavechange 🙂

I have manually removed snails and slugs, although only when there are large ones on the prowl. It’s all the little sluglets that are capable of climbing plants that are discouraging. They can be hidden and present in much larger numbers that the bigger ones.

Maybe beer traps are the way forward for environmentally safe slug control. They did work for my father.

Perhaps it is worth looking at what is happening in the commercial world, which has traditionally used methiocarb and metaldehyde for slug control. Methiocarb is to be withdrawn in the EU, and is probably no longer on sale. Methiocarb is a bigger problem than metaldehyde, one reason being that it is an insecticide and kills beneficial insects.

The Environment Agency is coordinating action with farmers and water companies to protect our rivers and drinking water supply from agricultural chemicals including metaldehyde slug pellets.

I would like to see metaldehyde slug pellets removed from garden centres. As mentioned above, there are ways of dealing with slugs in gardens, including accepting that some produce with be lost.

Lot of good sense in this collection of tips. I am a great fan of gravel as a mulch rather than plant material both because it is less friendly to slugs and because it dries and warms up more quickly in
burning sunshine!

“Control

Cultural controls: Mulch provides an ideal slug habitat so mulch lightly around plants that are attractive to slugs.
Water only in the morning so that the ground will dry by evening when slugs are naturally active.
Prune lower leaves or stake large plants to reduce potential hiding places for slugs and allow better air circulation which helps keep the soil surface drier
Trapping: Beer traps can be used early in the season, when the slugs’ favoured foods are more scarce, as slugs are attracted to the smell of beer. Such traps have various designs, but essentially the slug will venture into a half buried jar, or cut away plastic bottle, containing a small amount of beer (not stout or lager), succumb to the fumes and drown.
Physical removal: Night time patrols for hand collection can be useful. These can be augmented by regularly setting out traps such as boards, shingles, overturned flower pots, or grapefruit halves for slugs to hide under.
Barriers: Slugs have an aversion to copper. Copper pipe can be used and commercial slug rings are available. A 15cm length of plastic pipe with copper foil tape around it can be used to protect individual plants.
Repellents: Grapefruit and other citrus rinds, used coffee grounds, eggshells, and sharp sand can be used in gardens around plants to repel slugs.
They also find dry surfaces difficult to cross since they must extrude a wet slime coat in order to move and this can eventually lead to dehydration, so leave cleared borders or walkways around plants.
Pesticides: Commercial slug pellets containing metaldehyde or methiocarb are available, but are not approved for organic gardening as they can poison creatures at a later stage of the food chain.
Aluminium sulfate can also be used; its proponents claim that it is less toxic to the environment.
Salt will kill slugs, but is also poisonous to plants.
Organic pesticides: Diatomaceous earth is a natural abrasive that can cause small cuts or scratches on slugs, causing them to dehydrate.
Bait pellets containing iron phosphate are also used for this purpose.
The mixture of 50% water with 50% ammonia will kill slugs instantly. This can be applied using a hand spray bottle early in the morning or during a warm rain.
Alternate hosts: Comfrey can be used as a decoy by placing the leaves around plants to protect them. The slugs will eat the comfrey and leave the protected plant alone. This is a honeypot approach, and rarely effective as it merely increases slug populations in the longer term unless comfrey is used as a trap crop and the slugs are controlled on it.
Predators and parasites: Frogs, toads, snakes, ground beetles, ducks, pigs, birds.
Biocontrols (microscopic): A recent development in the control of slugs is the introduction of ‘Nemaslug’, a microscopic nematode (Phasmarhabditis hermaphrodita) that will seek out and parasitize slugs, reproduce inside them and kill them. The nematode is applied by watering onto moist soil, and gives protection for up to six weeks, though is mainly effective with small and young slugs under the soil surface. The nematode is only effective in warm, moist conditions, above about 20°C.”
Wikibooks

Rob Elmour says:
7 March 2015

I’ve used the nematodes. Not quite sure where Wikibooks got that figure of 20°C from. The ones I’ve used work once the temperature goes over about 5°C, which roughly matches the temperature when slugs become properly active.

They are spectacularly effective and apparently completely harmless to other species (even snails, unfortunately) They come as a kind of damp powder which is easy to mix with water and apply using a watering can, or you can use or a gizmo attached to the end of a hosepipe. However, an application only lasts a couple of months (I suppose when all the slugs are gone, the nematodes starve), they are expensive (about 12 quid to treat my garden) and they have no effect on slug eggs. Since slug eggs can lay dormant in the soil for over a year, you should really keep reapplying to clobber the little beggars as they emerge, before they have a chance to lay more eggs.

When I saw the headline for this Topic, I thought it was going to be about the general election, but actually it’s rather more fascinating than that.

We get a lot of slugs and snails. The birds seem to do a good job with the snails – there are broken shells all over the garden, especially near any ornamental stones which the birds use as an anvil on which to smash the shells. But the slugs have resisted all proprietary agents; I have been wondering if there is some form of birth control that I could administer [I can’t bring myself to behead them so I usually pick them up and take them into the woods nearby].

Vic says:
7 March 2015

It is also about the general election.
Most politicians remind me of slugs and snails.
The green party want human rights for slugs and snails.

I’m already bored rigid by the general election – it is just like a slow race between slugs and snails none of which know what they’re “running” for and are probably hoping they won’t win it. I’m just hoping the Monster Raving Loony Party steps into the breach again and livens things up a bit. Vote Snail – they do more for the homeless.

I can feel the hairs on the back of my neck sticking up as my collar is about to be felt for offending the Off-Topic Regulator.

len says:
4 March 2015

Work in farming
for 30 yrs when younger,
at a market garden and fruit farm,
and in all that time,
we never solved this slug prob,
When growing cabbages, lettuces, broad beans, runner beans peas ,
rose’s dailies’ iris’s, and so on
in fact anything young green and edible,
We use to farm over 600 hundred acres ,
Over night in warm wet weather you could walk down to a field of newly planted cabbages and watch them disappear in a matter of 6 hours 250k of new cabbage plants,
which had just taken 72 hours of sitting on a planter on the back of tractor and hand planting seeding every 8 inches and having 5 acres to plant.
.Then a later in week going to check cabbage plants,
and see fields of little green sticks and not a leaf left on over half of 5 acres of plants ,
: ¬{ 1971 spring was a bad year its was warm and rained a lot we got a lot of veg in early but payed dearly with slugs and snails caterpillars fungi ,
If we keep banning pesticide’s and fungicides and slug pellets /liquids,
and go with organics in food production on a global scale,
3/5ths of the world people will starve to death in a decade,
and most of them will be in the northern hemisphere ,
as it is,
No one have given a thought to how we grow food to support 11billion humans in 2050 and onwards ,
and when oil runs out,
Any changes we make to food production now,
You can be kind to slugs or what ever,
because in end,
it will be your great grand children that will pay for that kindness,
and bless you,
and hunt among the rubbish and rubble that was the world looking for a few slugs to eat,
or snails,
None so blind as those that do not want to see ,

Len – I agree that organic farming is not a solution for feeding the world. The losses of crops would be too high.

The problem is that some of the chemicals used in agriculture are simply not safe to use. Several neonicotinoids have been banned for two years, except for certain uses, in the hope of tackling the decline in bee numbers, though neonicotinoids are probably only partly to blame.

We urgently need to develop biological control agents that can replace or cut down the use of chemical pesticides. Typically they cost more, they are more difficult to store and more difficult to use, but at least they are safe. You are probably familiar with Btk and other safe pesticides.

In this Conversation we are discussing how to deal with slugs and snails in our gardens, which is rather different from large scale food production.

Perhaps we are approaching this from the wrong angle – maybe we should embrace slugs for our benefit by eating them (as some do snails). So harvest your garden pests for food – here’s a recipe I found for a stir fry http://forums.gardenweb.com/discussions/1886129/stir-fried-garden-slugs-on-angel-hair-pasta-recipe. Just don’t invite me round, please 🙁 Anyone got any recipes?

Stir fried slugs?! That sounds disgusting… Malcolm, this suggestion has reminded me of Patrick’s conversation about eating insects…

https://conversation.which.co.uk/consumer-rights/eating-insects-would-you-eat-edible-bugs/

You beat me to it Andrew. I wanted to tell you about the strangest Conversation that we have seen so far. I don’t fancy eating slugs any more than I would want to eat insects. I would rather turn vegetarian, assuming the slugs have not eaten all the vegetables.

Maybe Malcolm could arrange an M&S dine-in deal featuring slugs for two, plus a dessert of your choice.

And humans eating slugs would be a good example of biological control, though not one I’m keen to promote.

Haha, I remember watching the video some years ago and thought it was rather disgusting – I can’t believe Patrick and the team actually ate those insects!

I’m with you wavechange – I’d rather be a veggie than eat slugs… x_x

I can’t believe how much I paid for them…

Has anyone encountered the Spanish slug, sometimes reported to grow up to 150mm in length? Wikipedia gives a more modest figure of 80-120mm.

We haven’t come across this specimen yet but we keep the castanets handy just in case.

Stuff of nightmares Wavechange – why have I come over all nauseous? Have definitely gone off Patrick since watching the video!

Reverting back to my kindergarten days and nursery rhymes, where did the saying slugs and snails and puppy dogs tails, that’s what little boys are made of, whereas little girls were made of much more appetising stuff like sugar and spice and all things nice? I must confess to preferring the latter for my eating habits but, on second thoughts – no offence meant chaps – the same definitely wouldn’t apply to big boys I hope!!!

Don’t read the comments on Patrick’s video unless you want to learn about Casu marzu cheese, Beryl. 🙁 🙁 🙁

I think that Len’s post is a bit extreme, but he has a very important point about how dependent we are on pesticides and insecticides. We can probably cope in our gardens but feeding the world is another matter.

I felt slightly nauseous too, Beryl…

You’re all wimps 😉

Yes I came across the Spanish slug variety about two years ago . Huge blighters they were and they ate their fellow slugs when they caught up with them. Dropping them in a bucket salt water terminated their activities in my garden

The Charolais of slugs appears to be Limax cinereoniger at 200mm long – in most of Europe and on the loose in UK. Looks a bit like a walrus. Sounds like a bit of selective breeding could make for a new Sunday joint.

Parasites are its enemy (and probably ours if we eat it). I’ll keep an eye out for it in my garden, but its main habitat is woodlands and parks.

I can only sympathise with Len. I’ve lost carefully-nurtured plants to an overnight incursion of slugs and snails, brassicas to cabbage white caterpillars as well as gooseberry leaves to the sawfly caterpillar. But we do share this planet and need to find ways to live and let live.

The parasites are the nematode worms mentioned in Adele’s introduction. Harmful for slugs but probably little else.

“Okay, why cook them? People do eat slugs raw on a dare, and the Indians used live slugs to numb gums, tongues and toothache. These common little creatures aren’t too bad unto themselves, but some of the land crawlers especially in warmer areas have parasites, one of which they can get from rat feces. That parasite, normally infecting a rat’s lung, goes from your stomach to your brain, crawling there over time — yes, crawling there — and causes your brain to swell.”

I’m steering clear of them – and inspecting my salad lettuce very carefully before I chew it. 😀

Note to self: don’t eat slugs raw.

Question: Does Casu Marzu Cheese really contain live insect larvae?

Oh Dio mio!!!

I believe so Beryl…live maggots crawling about in it…Yuck!

Wikipedia says “Derived from Pecorino, casu marzu goes beyond typical fermentation to a stage most would consider decomposition, brought about by the digestive action of the larvae of the cheese fly Piophila casei. These larvae are deliberately introduced to the cheese, promoting an advanced level of fermentation and breaking down of the cheese’s fats. The texture of the cheese becomes very soft, with some liquid (called lagrima, from Sardinian language for “tear”) seeping out. The larvae themselves appear as translucent white worms, about 8 mm (0.3 in) long. When disturbed, the larvae can launch themselves for distances up to 15 cm (6 in).”

Apparently it tastes strongly of ammonia and the taste can last for hours (Brie has a mild ammonia smell, doesn’t it).

It makes slugs seem positively palatable.

Apart from putting us off our tea, this is a bit reminiscent of a scene in “Monty Python’s Life of Brian” where snack vendors were going round the arena offering Ocelots’ Nipples and other tasty titbits to the excited throng.

Maybe we should get back to how we can cope with slugs. Has anyone tried the biological control approach using nematodes, as mentioned by Adele in her introduction.

There is some useful info on the Royal Horticultural Society’s Website re slugs and nematode treatment and quite a long list of supposedly slug repellent plants, although they still enjoy eating the young shoots on my hydrangea petiolaris @rhs.org – Slugs.

Been members for years.

Great organisation with an excellent robust Constitution. Its amusing that Jekka McVicar because of a Trustee role reported £37.00 for herbs to Hyde Hall. Mind you all the RHS Trustess do.

And also very far sighted in that the life membership is 100 years from joining or death. An dyou cannot join until you are 18.

Thanks Beryl. I looked at the RHS site at the start of this discussion and they list half a dozen suppliers of nematodes.

Having now looked at one commercial product – ‘Nemaslug’ – I have been able to confirm that the nematodes have to be ordered when needed. They will keep for up to four weeks in the fridge. Keen though I am on biological control, I’m not keeping nematodes in my fridge. Maybe if a local garden centre starts stocking them I will give them a go at my slugs.

Here’s a pretty comprehensive list of measures for trying to control slugs.
http://www.slugoff.co.uk/information/list
Since they lay up to a hundred eggs several times a year I wonder whether nematodes really have any chance – particularly in a garden of any size. Just spend the money on more plants instead?And slugs have a role in devouring decomposing garden vegetation, in providing food for birds, and for each other. Cannibal slugs may be another way forward – but then you have to control them. Banging your head against a brick wall?

I now know what slug eggs look like and it would probably help to destroy these, either by standing on them or with a small amount of slug killer. I will mount a slug attack this year.

Good luck with you egg hunt. They lay them under stones, pots and so on as well as in holes in the ground.
Snail caviar is, I believe, maketted. So rather than stamping on your slugs eggs maybe you could open a delicatessen?

I have always wondered what the eggs were when I have seen them in the past. Definitely ghastlypods. 🙂

If you go out armed with garden hoe and turn the soil over to expose the slug eggs, there are plenty of hungry nesting birds in the garden at this time of the year to oblige. It may not clear all of them but may reduce their number a little.

Lesley B says:
7 March 2015

I consider slugs to be quite intelligent and very discerning, they always go for the plants and seedlings I have nurtured,usually the most expensive ones, but all the weeds seem to flourish without a sign of damage, I then think they’re sitting back watching me with my aching back and burning knees, spending hours weeding borders and clearing a clear path for them straight back to what plants I have left. I get the feeling there’s a sluggish plan afoot!

Jeoffry says:
7 March 2015

Armed with a plastic bucket containing warm highly salted water and a dedicated fish slice, I roam the patio and paths in the dark. Forty a night is a good haul. Yes, I know killing is nasty but the deaths are instantaneous.
I feed the birds,- – and I stopped growing hostas.