Slugs and snails are one of the greatest enemies of the home gardener. They can devastate a garden practically overnight. For the purposes of this article we will refer to slugs but all information applies equally well to snails.
Slugs will eat practically anything you plant. I have even had them eat the foliage of onions, garlic and jalapeno peppers in my garden. They are especially fond of lettuce, tomatoes, beans, asparagus and cabbage.
From my experience, the only way to completely eliminate snails and/or slugs forever...is to live where they do not exist. Maybe the Sahara Desert...or the North Pole? The point is that slugs exist practically everywhere conditions allow plants to grow. So, accept the fact that if you grow a garden, you will probably have slugs to some degree. The goal is to be able to keep more of your plants than the slugs take.
Determining If You Have Slugs
Slugs are night feeders, therefore you may never see one in your garden during the day. If you have planted young, small plants and found they are completely gone the next day, you probably have slugs in your garden. On larger plants with leaves close to the ground you may find large holes in the leaves.
To determine if you have slugs, look for their clear, silvery, mucous trail on the ground near your plants. Also, go out into the garden just before daylight with a flashlight and look. You will probably see them, especially if the ground is moist.
What You Can Do
Clean Up The Garden
First, remove all of the slug's hiding places from your garden and nearby. Rocks, wooden boards, grass or weed clippings are all home to slugs. Get rid of them. Your garden should look like bare ground (surrounding your plants). Also, tie up plants so that there are no leaves or vegetables touching the ground. Even cucumbers can be trained to climb a trellis so the cukes do not touch the ground.
One method, although labor intensive, is to go out in the garden every morning right before dawn and hand pick the slugs. Do this until you can not find any more.
Beer In The Garden
In conjunction with the above you can use the old method of placing small containers of stale beer in the garden. Just take a small container like a tuna can, fill with beer and bury up to the rim throughout the garden. The slugs are attracted to the beer, fall in and supposedly they drown (I have never tried this method since the beer mysteriously disappears before I make it to the garden).
Another method is to place a copper strip completely around the garden. It is said that slugs will not cross the copper. You can buy copper strips made for this purpose at most garden shops. I have tried this and found it helpful but not a solution.
A method I've never tried but should be mentioned...you can buy Decollate Snails or (sometime referred to as Decollata Snails), a predator of slugs, and place them in your garden. You can find them on the internet (search for Decollate Snails). The drawback is that they are not legal in every location and it takes about 2 years for them to be effective. So they will not cure the problem right away. But you may want to try them for a long term solution if they are legal in your location.
You can buy snail/slug baits at your garden shop or home improvement store. These products are effective, however WE STRONGLY DISCOURAGE using any baits except under specific conditions (described below). These baits are poisonous and can cause sickness or death to animals, small children and wild life (dogs are attracted to it).
You may have seen some slug bait advertised as "Pet Safe". Studies have reported dog poisoning caused by these so-called pet safe products.
It is true that the ingredients listed on the label of these "pet safe" products are relatively safe. The ingredients label list only iron phosphate and inert ingredients. Iron Phosphate occurs naturally in nature and you can find many references that indicate it is and is not poisonous. Some references indicate that it is not poisonous to snails however it disrupts their digestive tract causing them to stop eating. Thus they die from starvation.
So, how does "pet safe" snail bait work? It works because one of the inert ingredients (not identified on the label) is sodium ferric (EDTA). When EDTA is mixed with iron phosphate it makes it deadly. It is not listed on the label because no regulatory agency requires inert ingredients to be identified on the label.
Do some research on "pet safe" snail bait and decide for yourself before using them. Google "EDTA in snail bait" and read this article..."Iron Phosphate Slug Bait - How Dangerous is it in the Garden"
If you choose to use any snail bait only use it in an area that is completely isolated from pets and children (a locked greenhouse or fenced garden). Personally, I would not put any substance in my garden that will kill animals, especially around vegetables I intend to eat.
THE BEST SOLUTION
We believe the best deterrent to snails and slugs is food grade diatomaceous earth (DE) pronounced "dia-toh-may'-shus", which can be difficult to find but is generally available at most health food, natural food stores and Amazon online. Be sure to get "food grade" not "pool". The pool product used to clean swimming pools has harmful additives and can harm your plants and wild life. Also be careful of DE sold in garden shops which generally contains harmful additives to speed up the effectiveness of the product. If it does not specifically say "food grade", do not use it. Food grade diatomaceous earth is totally harmless to you, your pets and all mammals. You can eat it if you want (don't know why you would want to).
It kills crawling insects like roaches, snails, fleas and ticks by dehydrating them. It has some drawbacks such as it must be reapplied after rain and it takes several days to rid your garden of snails but it works and is safe.
As a sidenote...if you pets and have ever have fleas invade your home, food grade DE is the best solution. It takes two to three weeks to eliminate fleas but it will definitely get rid of them without using any poison.
So, how do you get rid of slugs? There appears to be no magic formula. If you apply every method described here you will probably still see an occasional slug. But, by using a combination of these methods you can control them with the following program:
1. Start working on eliminating snails and slugs in the spring (even before you have plants in the garden)
2. Place several buried containers of stale beer around the garden. It's easy and little maintenance.
3. Go in the garden at least every 2 days, in early morning, and hand pick any visible slugs.
4. Use copper strips.
5. Use our top recommendation, food grade diatomaceous earth (DE).
6. Be persistent.
You will find, with this routine, that it becomes more and more difficult to find any slugs and the slug damage to your plants diminishes. It is very difficult to completely eliminate all snails and slugs all summer long in your garden. But you can reduce the damage caused by slugs to an acceptable level.