Control Methods for Slugs

Resilient Life Public Resilient Life
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I absolutely loathe slugs. They are a huge pest in my strawberry patch, and a minor pest in my annual garden. I mulch my garden with either shredded hardwood or straw, and I definitely have more slug problems from mulching. Having said that, the benefits of mulching far outweigh the slugs. I have tried quite a few natural and home remedies that can work wonders at keeping your slug problems to a minimum.  Join me in exploring the numerous options we have at our disposal. 

Control Options

1. Beer Traps

Save your tuna cans, clean them out, then set them in the soil so the top of the can is at soil level. Then fill with beer. The yeast in the beer attracts the slugs. They fall in and drown in the alcohol. I used this method with moderate success last year, but to be honest it’s kind of expensive, unless you have a free source of outdated beer. If you can get free past due date beer, this is a decent method. You just need to install a lot of traps, at least one per 10 square feet. Hence the reason free beer is important. Also, I think tuna cans are as shallow as you can use. I tried old mason jar lids, because I would need a lot less beer. I watched a slug fall in it and crawl right back out. The walls weren’t steep and deep enough.

Cost: High, if you are buying the beer

Effectiveness: Moderate, but you need a lot of traps

Labor: Moderate, you need to install the traps then change out the beer every couple of days

2. Placing down plywood next to affected areas

You can place sheets of plywood down, and during the day the slugs will gravitate to the wet area under the plywood, then you can simply lift the plywood each day and kill all the slugs. Well in theory that sounds good, but I got very few slugs with this method. Ultimately, it wasn’t worth the effort.

Cost: None if have some old plywood laying around.

Effectiveness: Low

Labor: Moderate, you do need to check under the boards each day.

3. Copper wire

I know of some gardeners that put copper wire or ribbon around vulnerable areas of their garden. Apparently, it gives the slugs an electric charge. I have never tried this, but given the cost of copper, I can’t imagine this is a cost effective solution.

Cost: High

Effectiveness: High

Labor: High (Imagine putting copper ribbon all around your garden)

4. Eggshells

Some gardeners will take their egg shells clean them, crush them up, and place them around vulnerable areas. I have tons of eggshells, but I am skeptical of the effectiveness of this.

Cost: None

Effectiveness: I don’t know.

Labor: High. I think it would be a pain to clean, break apart, and spread out enough eggshells to make a difference.

5. Diatomaceous Earth

Similar to the eggshell idea, if you sprinkle this around, when the slugs go through the DE, their bodies are ripped open by the jagged fossils. This is not a bad idea, but it gets expensive, because you have to reapply after rains.

Cost: Moderate

Effectiveness: Good

Labor: Moderate (You don’t have to clean and grind up the DE, but you do have to reapply after rains)

6. Sluggo Organic Bait Control

Sluggo bait is iron phosphate, so it is safe to apply to your garden without fear of damage to your ecosystem. This organic control is very effective.

Cost: Moderate

Effectiveness: I had great slug control with this product.

Labor: Low

7. Irrigation

It is important to not irrigate in the evening. You are creating a slug sanctuary if you do so.

~ Phil Williams

Phil Williams is a permaculture consultant and designer and creator of the website foodproduction101.com.  His website provides useful, timely information for the experienced or beginning gardener, landscaper, or permaculturalist. Phil's personal goals are to build soil, restore and regenerate degraded landscapes, grow and raise an abundance of healthy food of great variety, design and install resilient permaculture gardens in the most efficient manner possible, and teach others along the way.

This is a companion discussion topic for the original entry at https://peakprosperity.com/control-methods-for-slugs/

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You don't mention Decollate Snails as an option, but you might consider giving them a try.  I have horrible issues with snails and slugs, and the typical San Diego landscape (lots of over-watered dense shrubs) is a breeding ground for them.  I have tried the beer trick, and had very little success.  I have also tried coffee grounds, which are supposed to be bad for them (I think the caffeine is bad for them?), but had minimal or no success.  I've done the copper thing, which worked fairly well for one strawberry pot, but was too expensive and difficult for the rest of my garden.
Sluggo definitely works (I used the organic version).

Decollate Snails (http://en.wikipedia.org/wiki/Decollate_snail) also worked well.  I put some down each of the last two years, and this year I am seeing them here and there, and seeing fewer snails and slugs.  They are relatively low cost, and are super easy.  Note that Sluggo kills Decollate Snails, so I use Sluggo as a perimeter defense.

The final suggestion I don't see here is the manual hunt and destroy missions.  I go out nightly with a flashlight just before bed, pluck and chuck snails (hard into the fence, usually), and stab the slugs.  I try to feed the Decollate Snails with the carcasses.  :)

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You forgot to mention ducks, who turn slugs into tasty eggs!

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A DAY IN THE LIFE OF A SLUG:
Slugs are mollusks that live in moist, cool, and dark environments. They sleep and/or hide during day light hours and dine at nighttime leaving behind a slimy secretion that lead back to their food sources.

Aeration

Change the environment around your plants greatly reduces the slug’s environment. This is when pruners come in handy. Open up the plants air flow. Stand back and look at the plant being attacked by slugs. Is there an open space below the lower leaves of the plant; between the soil and the lowest parts of the plant? Prune any branches on or near the ground often you may have to prune several to open this air passageway. The soil will now dry out from rain and/or dewdrops. After pruning in this area step back and look at the center of the plant. Are there openings for air in the center of the plant? If not this is a good time to prune a FEW in the center. This creates one more flow passage for air and sunlight to dry the center of the plant. May have to repeat pruning if there is a lot of rainfall through the grow season.                                                Just this simple maintenance will reduce slug’s populations by over 50%.

Disrupt their traveling pattern

There are other old fashion remedies that also work. Place a FINE ring of “pot ash” around plants that you want to protect. “Pot ash” is the fine gray ash from burning wood. The ash irritates the skin of the slug and they will not slime across the ash. Just be careful not to use too much ash as it can after time affect the pH of your soil.

Be cruel

During the early first light of day go to the area being attacked by the slugs armed with a salt shaker. Turn over leaves of plant until you find some slugs and sprinkle them with salt. Their bodies will literally melt before your eyes. It only takes a few grains of salt and it will kill them. Be careful not to get it on your desirable plants as it will also burn holes in their foliage when the sunlight reaches the plant. Just like the “pot ash”, do not overdose your soil with salt as it can also affect soil pH.

Attract birds & reptiles

Birds and reptiles will eat slugs so it helps to plant a food source for our feathered friends.

 

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Three methods have worked well for us.

  1. Attract thrushes to the garden, opartly you do this by not trying to control the slugs and snails at first. You don't have a pest problem, you have a predator deficit problem. The more successful you are in getting rid of the pests, the fewer predators you will have. That means some sacrifices at first. We have a great population of thrushes and, in our previous garden, slugs and snails were very hard to find. Still working up in our new garden but already slug problems are few and far between.

  2. Use mulch made from very strongly chemical bearing trees. We had great success with camphor laurel mulch which stopped them dead. It wears off after about a year so you will need to rnew it and out problem is that they are pest trees that were being removed so we ran out of a source.

  3. Plant out bigger seedlings and then don't kill the leopard slugs, limax maximus, they prey on other slugs but they also eat very young seedlings.

We are still working in a new garden but in our old garden we had raised beds with alyssum growing over the edges and down the boards. The snails especially used to hide there during the day so finding them was dead easy and, by the end of our time there, we had trouble finding them even there, thanks mostly to the thrushes.