Non-Toxic Slug Control

The best way to combat slugs is to understand their life cycle. Slugs themselves are composed of a high percentage of water and will begin feeding as soon as soil temperatures rise above 40 F (5 C), emerging from the soil or from protected areas. Slugs prefer to forage at night or on dull days when temperatures drop and the garden is damp. Their gelatinous eggs, laid in clusters of 40-100, can be found in the soil, under rocks and even in outdoor pots. Learn to recognize them!

Cultural Methods of Control

There are many simple things you can do in the garden to decrease slug damage. Because slugs are made up of so much water, they are very susceptible to drying out. In the early spring, cultivate your soil to expose their eggs to drying air & predators. Try to keep your garden as dry as you can without damaging your plants. This can be achieved by using drip irrigation or soaker hoses rather than overhead sprinklers. In addition, if you mulch your garden, keep the mulch well back from the base of susceptible plants. Better yet, consider waiting until temperatures rise above 75 F before you apply your mulch. Slugs also love warm compost piles so if you can, keep your pile separated from the rest of your garden.

Handpicking

Handpicking is an extremely effective way of riding your garden of hundreds of slugs. For the squeamish, chopsticks, tongs, or even hatpins can be used to catch the offending pests. The best time to hunt for slugs is 2 hours after sunset so take a flashlight. Finish the slugs off in a bucket of soapy water.

Attract or Repel?

Most gardeners choose either of these methods to prevent slug damage in their gardens. Attracting slugs into baits or to trap crops and then discarding them is a popular system.

On the other hand, preventing them from getting to your prized plants is also important. Here are the basic principles:

Baits

Slugs are attracted to chemicals given off by the fermentation process. The most popular bait has been beer. However, not all beers are created equal.

In 1987, a study at Colorado State University Entomology Professor Whitney found that Kingsbury Malt Beverage, Michelob, and Budweiser attracted slugs far better than other brands.

The range of slug traps is only a few feet so you need to supply a few throughout your garden. Never, sink the containers with their rims flush with the soil level or you run the risk of drowning ground beetles, important slug controllers. The rims should be 1" above the soil's surface.

In the last couple of years, a new product has been released into the market that is receiving rave reviews from organic gardeners. Baits made from iron phosphate have been found to decrease slug populations without harming birds, small pets or humans. Scientists are still not sure exactly how these elements affect slugs but figure that they inhibit the slug from feeding anymore. The baits are sold commercially under the name Sluggo, Es-car-go, and Safer's Slug & Snail Bait.

Trap crops

Certain plants seem to be favored by slugs and can be used to divert slugs from your prized plants. Particularly good trap crops include: green lettuce, cabbage, calendula, marigolds, comfrey leaves, zinnias and beans.

Barriers

Certain plants will also repel slugs. Ginger, garlic, mint, chives, red lettuce, red cabbage, sage, sunflower, fennel, foxglove, mint, chicory & endive seem to be less prone to slug attack. Plant them around the perimeter of your garden to keep them from infiltrating.

Aside from diverting slugs to where you want them, gardeners can also use certain barriers to keep slugs out of particular spots. A ring of abrasive material such as eggshells, sand, wood shavings, diatomaceous earth, hair or ash can be placed around susceptible plants. These materials do have to be kept dry, however, in order to work. After rains, top them up again. Cutting the tops and bottoms off of plastic containers and using them as a cylinder around young seedlings can construct a more permanent barrier.

One of the most effective barriers, however, seems to be copper tape, as it works wet or dry. When slugs and snails make contact with the copper, there is a toxic reaction, similar to an electric shock, which repels them. The minimum width for the copper barriers needs to be at least two inches; slug barriers sold in nurseries are often smaller and should be doubled or tripled when installed.

Slug Predators

Many natural predators will eat slugs. Providing a habitat for them will help build their populations so that you do less work in the long run. Slug predators include:

* Ground beetles - Like to live under wooden boards during the day.
* Frogs - They prefer damp sites & a quarter of their diet may comprises slugs.
* Birds - blackbirds and thrushes, robins, starlings, rooks and crows, jays, ducks, seagulls and owls will eat slugs

There are a number of tools that a gardener can use to combat slugs. Handpicking, traps, barriers, baits, & predators are just a few techniques. So, rather than shrugging off slug damage as inevitable, choose from the slug control menu and you'll be surprised by the results.

The Author:

© Copyright 2002 Arzeena Hamir

Arzeena Hamir is an agronomist and President of Terra Viva Organics. Grow a healthy, pesticide-free garden for you and your family. Our site includes organic growing advice, organic fertilizers, natural pest controls, weekly tips, feature products, and a monthly newsletter.

10 Responses

  1. Vi

    Some good advice here thank you, however I have to say however that
    in my experience sunflowers are not a deterrent flower as slugs& snails have eaten all mine!

  2. Kerwin Maude

    There are many ideas shared by bloggers and experts about pest control that work to their credit. A neat way to kill these slimy destructive nuisances is to use table salt and sprinkle it lightly about 3 feet away from plants, flowers or veggies to form a barrier. The slug or snail will cross over it and the salt crystals will stick to its underside and melt it like acid into a gooey glob. Reapply salt after rainy periods or watering lawns it is much better than slug baits that could be harmful to pets, and curious little children and more. Salt is cheap, try it and enjoy your gardening. I agree with Vicki M, and if you want to whack pesky ants use a 50-50 mix of borax and icing sugar it is effective and cheap. The ants will be wiped out in no time, and remember ants are resilient buggers so reapply a sprinkled light coating about 3-5 weeks after. If you have them invading your pantry, place a small amount of the borax/icing sugar out of reach of young children and then they’ll hit it and then take it to their nest like a time bomb. Good luck….why buy ant traps and chemical sprays that are dangerous to inhale and toxic to plants, children or pets?

    Kerwin Maude

  3. Norm G

    Interesting that a Pioneer Thinking site dealing with an article on slugs makes no reference or citation to how pioneers actually dealt with slugs and snails. Would really like to know….and not conjecture or anecdotal conclusions. PS No documented studies support garlic, etc, as barriers to slugs in gardens….a lot of that is myth.

  4. MARGARET C.

    Slugs and Beer

    If you do have slugs, pour some beer into an aluminum pie pan and set in the sun. The slug will crawl into it but can’t crawl out. Just throw away the pie pan. If you gotta go, I could think of worse ways. (And no, it doesn’t have to be any particular brand or style of beer.)

  5. VICKI M.

    Old Time Try To Kill Slugs

    My grandfather showed me how to kill slugs when I was a little girl. All you have to do is put salt on them or around the base of a plant. Putting salt on the slug will cause it to shrivel up and die. Putting the salt around a plant or the whole edge of where plants are will keep the slugs out plus kill them off. Hope this helps people get rid of their slug problems!!

  6. Bill

    I just finished reading your article about slug control and thought I’d pass this tidbit along.

    I’d like to suggest that a generous sprinkling of fresh (unbrewed) coffee grounds has, for the past two years, allowed me complete control of grubs.

    The first year I had tried ferrous phosphate and achieved partial control. However, a few weeks later, the problem returned. I did not want to continuously add this chemical to my soil because I did not want to have a build up of it. So, on a hunch, I tried the coffee grounds and got control that lasted the balance of the season. This spring, I waited for the first signs of trouble and re-applied the coffee grounds.

    I have not seen any slug damage or trails since.

    This builds on research conducted by the University of Hawaii into the effect of caffeine on amphibians.

  7. MARK S.

    I am living here in Maidstone, England and battle every summer with slugs in the garden, BUT I have found the remedy to all of your pesky problems with slugs whether it is large or small.

    There are countless remedies on the market which range from Nematodes to beer to harmful poisons and concoctions that I would not trust alongside my herb garden that is used for cooking and eating.

    I stumbled upon this sure fire remedy one day purely by chance and it has been the saviour of my garden. It closely resembles the attractive properties of beer but at an incredible rate without harmful poisons or expensive nematodes….what is it? If you use beer, you will attract a few, but you have to keep replenishing the beer everyday to keep it fresh and attract the slugs.

    Take a trip down to your local bakery and tell the butcher that you want to purchase some of his bakers yeast, or you can find it in your local grocery store if they carry it. You have to have fresh bakers yeast, it comes in a block and looks like white putty…dry yeast will not work.

    Take the block of yeast and cut off a chunk, mix it in warm water, add salt, and set it on your back patio or near your garden. If you think about the beer remedy, you will discover that the slugs are not attracted to the beer, but the smell of the yeast in the beer.

    I discovered this remedy one day after baking fresh bread with fresh brewers yeast and then decided to leave a piece of it out for the birds. I left it for about an hour and before I knew what had happened, there were hundreds of slugs making a bee line dash for the bread….EUREKA! It’s the yeast I said! I then went out and picked up each one with a scoop and put them all in a jar of salt water and that was that.

    Be prepared…if you use this remedy, you will have to keep checking it every hour cause if there is a slug within a hundred yards of your garden, you will attract it.

  8. REGENIA P.

    I’ve heard that a jar lid filled with beer sitting out for slugs to enjoy will promote drunk happy dead slugs.

  9. Tom R.

    Hi, I am a 14 year old boy and I have tried everything to get rid of slugs, the best way I have found is to lay some cabbage leaves down on the ground of your garden (this will act as a home for slugs), and after 3 or 4 days you go and get all the slugs from under the leaves. Do this a few times till you have a fair wod of slugs collected in a jar, then blend the slugs up in a blender with enough water to make the mixture so you can spray it back around your plants.

    This WILL work very well, the slugs will never go near the slug mixture.

  10. NJE316

    After trying everything to kill snails in sub tropical south Florida I have found a free, effective preventative for my bulbs and flowers. Used coffee grounds sprinkled around the base of attacked plants seems to be working in wet and dry.

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