Slugs – You Can Control Them

Slugs are creepies that no one enjoys dealing with.  Even when you think they’re not on your your property or in your garden — rest assured they are.

They’re part of the system set up to break down decaying matter. And I for one wish they would stick to that rather than getting on my lettuce and other crops they consider gourmet fare.

You’ll be glad to know that out of all the slugs existing on your property you’ll see no more than 10% of the population because the other 90% are busy underground doing their job. (At least that’s what scientist who study slugs say.)

A Reader’s Concerns

A friend and reader of TMG, Sandra, left a comment recently saying that her slug problem seemed really bad where she had heavily mulched. She went on to say, “I want to love the deep mulching, but these slugs are making it difficult.”

I emailed Sandra with lots of questions to get a better understanding of what was happening in her garden.

First Year for Mulching

She started mulching because she has seen what my garden (and borders) look like and wanted similar.  She finds it most appealing that I spend little time weeding, don’t have to add fertilizers, or water, and that my soil is “fabulous”. (My soil is very good — but better in some areas than others.)

Not the First Year for Slugs

Although this is the first year Sandra has mulched — it’s not the first year she’s had slugs.

As would be expected this year’s rains made her problem with slugs worse.  (Slugs love moisture. And mulch or not — they’d be around.) She recognizes that in years of drought — you just don’t see as many slugs.

No Consistent Control for a While

Some time back Sandra had chickens. She thinks the population of slugs has probably been growing since they’re not around for consistent control. I would definitely agree. Killing off those great big ones that lay the most eggs really makes a difference in the population. As does killing the eggs you find in the soil — which I’m sure the chickens took care of.

Night Hunting

Years ago the only control option I had was handpicking.  I was diligent.  I went out at night with my flash light in hand and killed those big 3 inch monsters.  Cutting them in half got so creepy that I resorted to pouring Morton’s salt on them. Pouring salt on  top them will stop them in their tracks, but not kill them instantly. (If you use salt on them — put them in a container — then you can dispose of the entire thing later. Salt increases soil salinity so it’s not good to put it on them in the garden.)

I had no idea then that many other gardeners used handpicking as their control for slugs. Mother Earth News recently did a survey on the success of control methods for slugs and handpicking was highly rated as a control measure with an 87% success rate.

Is Mulch Responsible for Slugs?

It really never entered my mind years ago that mulch had anything to do with slugs getting into my stuff one way or the other.  There are many who disagree with me  — as I have read in various accounts over 35 years. And yes, I do understand that mulch gives slugs better conditions, but I’m living proof that you can garden with mulch without a lot of slug damage. Diligence is about all that’s required.

I will say this — you are far more likely to find a slug under mulch anywhere in your garden than you are on sun baked unprotected soil. Certainly there would be nothing there for slugs — or anything else for that matter.

I don’t wage an all-out campaign to get rid of every slug on my entire property. (Trying to get rid of all of them would be an effort in futility anyway.)  I do it very selectively.

We have a little over an acre of ground.  Other than the house, two sheds, the driveway and a little bit of grass — it’s all borders and gardens. AND – they’re all mulched.  I have very little slug damage.  The slugs prefer a few daylillies (out of 150 varieties) and they love garden vegetables — some better than others. So I only target control where I know they will or are doing damage.

Less Trouble as Time Passes

When I first started gardening (and I’ve always been a mulch gardener) I had more trouble with slugs than I do now. Although I’ve learned to accept that they’re part of the scheme of things and they’re gonna be around, I’ve also learned to control them and the damage they can do and have been successful. You can do the same with a little effort, diligence and a better understanding of your options for control.

Controls other than Hand-picking and Salt

ESCAR-GO (or Sluggo)

I don’t go hunting at night anymore. I used Escar-go (before they added Spinosad) as my method of control for probably 20 years with great success.  I use it when needed and with all the mulched areas that I have, I only use one box (if that) per season.   I only use it when and where there are signs of damage or if I know from the past there will be damage. Even though it was suppose to be perfectly safe I think it’s always good to be conservative with things that kill even if they’re approved for Organic Gardens. And I would keep it out of the reach of children and animals no matter how safe they say it is.

How it Works

The slugs are attracted by the wheat gluten in the Escar-go.  They eat the bait and stop eating almost immediately.  They crawl away and  die 3 to 6 days later.  So you may never see them.

Here are some examples of how I use it:

• If I see damage to certain daylilies I sprinkle the Escargo (now Sluggo) around them and into the leaves as well.

• They were eating my broccoli and cabbage seedlings this spring until I encircled them with a  sparse ring of Escargo (now Sluggo). It stopped the damage.

When I pick lettuce on cloudy, overcast days — or when it’s drizzling rain — of if the dew hasn’t dried yet — or if the sun has been off the lettuce too long when I pick — I can expect to see slugs.  I don’t see the big ones anymore — and haven’t for years — but what I do see sometimes is when they hatch out. Here’s what I mean:

• One cloudy, overcast day I went out to pick lettuce.  I walked into the garden to the first beautiful section of red lettuce and was horrified to find it covered with hundreds  of tiny slugs.  How sickening.  None of the other patches of lettuce were like this.  So — I assumed they hatched out in this area and attacked the lettuce.  I immediately sprinkled the entire area AND circled the lettuce patch sparsely with Escargo (now I use Sluggo).  And just to be on the safe side I broadcast it over the rest of the immediate area.

The problem was resolved by the next evening.  After that – if I picked lettuce after the sun had been gone from the lettuce for an hour or so — I would see several small ones —-but nothing like that day I saw hundreds.

Keep in mind — if you still have the big slugs around in numbers — they have to eat more of this stuff before they’ll die.  Once you get the big ones gone — it’s much easy to kill off any small ones that hatch.  You just have to be diligent.  Maybe even combine several methods of control like hand-picking and Sluggo until you get the numbers down.

How Some Gardeners Use  Sluggo and Why I Wouldn’t

There are gardeners who scatter Sluggo over the entire garden. And they do it again every two weeks in the spring and then once a month and then every two weeks in September. Even though this is a product that is approved for Organic Gardens — the idea of using it over that great an area and for all that time — sends up all kinds of warning signals inside of me that it’s not a good idea.   There have been too many things that were suppose to be safe and then ended up not being quite as safe as was thought.  So when I use this product, I’m moderate and I would suggest you may want to be as well.

Also, read the instructions before you use it. The Mother Earth News survey gave it an 86% success rate.

Diatomaceous Earth (DE)

Diatomaceous Earth (DE) (see source at the end of post) is made from tiny fossilized water plants and is all natural.  When slugs crawl through DE it adheres.  The tiny particles with their microscopic razor sharp edges are absorbed and eventually can kill the slug. Like Sluggo it doesn’t kill instantly.  It is most effective when used in dry conditions.  It has little effect when it absorbs moisture, so you’ll have to reapply after rain.

I covered more about Diatomaceous Earth in my post on Squash Bugs. Remember – use food grade and don’t breath the dust.

I’ve ordered this to keep on hand for my garden.  It’s an excellent product when used in dry weather and 100% organic. The survey by Mother Earth News gave it an 84% success rate.

Beneficial NEMATODES

Beneficial Nematodes are live microscopic organisms that occur naturally in the soil throughout the world.  Somehow — someone found a way to make them available to gardeners and believe me – they work!  There are all kinds of varieties of nematodes and different ones kill different things.

Our Experience with Beneficial Nematodes

In our early years of gardening we wanted some cow manure and had no way to get it but to go over to a nearby pasture and collect dry “cowpies”. We ended up with a pile about 3 feet high and 3 feet wide.  When we finally dug into it with a shovel we were horrified to see what seemed like thousands of grubs!

At the time I had never used beneficial nematodes before and had no idea if they worked or not.  Nonetheless, I ordered them.

We watered the pile of manure first.  The proper time to apply the nematodes is in the evening. So we mixed the dormant nematodes with water in a sprinkling can and applied them to the pile.

The next morning the pile was total free from grubs! Not even one remained!  It was the most amazing thing I have ever seen.

Nematodes that attack slugs

I’ve recently learned there are nematodes that will attack slugs.  Scientists at the government research institute at Bristol, England discovered them. And as far as I know, no US company offers the ones that kill slugs.

You can buy them online in/from the UK. But nematodes are a perishable, living product and must be used within a certain time frame.  Do your homework and be sure you can use them properly before you purchase.

OTHER Control Measures that have varying degrees of success

• 10% Amonia / 90% water spray

Amonia takes extreme caution because of its fumes.  You certainly don’t want to breath it or get it in your eyes. It doesn’t appeal to me at all.  But I mention it because I read about a man who raised award winning hostas and used this method to keep the hostas totally free from slug damage. He sprayed them once a week and while his friends who raised hostas a few miles away where overrun with slugs — his hostas were free from any damage.

This spray works by contact.  You have to spray it on the slugs to kill them.  It kills them quickly.

Since it is said not to affect plants adversely ( and obviously hostas do great being sprayed with it) – this would be perfect to spray on slugs that may be hiding close to plants or in the crown of various plants. (I still think it might be wise to test this on one plant or part of a plant first – just in case – before using it widely.)

TIP: Slugs hide from the sun.  Kill many at one time by placing an old board, a piece of carpet, a thick layer of wet newspaper, or anything they can hide under in a location that is prime for slugs.  Then just before the sun leaves that area, lift up board, carpet or newspaper and spritz all of them with amonia water.

TIP: Slugs come out of the ground after a rain fall.  This is good time to hunt them with you spray bottle in hand.

• 50% or more vinegar/and water spray

This is another spray that works by contact.  It may not be instant kill, but it’s fast. Vinegar can harm your plants — so careful not to get vinegar on them.

TIP: If you’re handpicking, put them in a container with about 2 inches of vinegar.  They die instantly.

• A 2% Caffeine Drench

A caffeine (coffee) solution has been found to be very effective in protecting crops from slugs and snails.  Soil drenched with this solution can kill up to 95% of the slugs and snails.

I think this one sounds like a winner —- especially if you’re a coffee drinker.  Idea: I’d be tempted to soak any newly planted lettuce beds with a coffee/caffeine solution. Just keep in mind that heavy rain will dilute the solution and it may need to be reapplied.

If you want to read a bit more about the research done on this, here’s the link.

• Used Coffee Grounds

Since caffeine is a nature repellent — if you have used coffee grounds on hand—- why not mix them with your mulch around your prized vegetables.  It won’t get rid of all the slugs, but I’d bet it would cut down on their damage.

Just another tool in your arsenal of weapons.

• Dispose of Slug Eggs you Find

Slugs mate and lay eggs all season in crevasses in your garden. Peak egg laying times are March/April and September/October.

If you find them when you’re going through soil, destroy them. Slug eggs look like fish eggs or pearls. You can find them anywhere that is moist and dark — even in the bottom of your flower pots.

• The age-old Beer Trap

This is the first method of killing slugs that I ever read about more than 30 years ago.

Half bury a container that has at least 2 inches of beer in it. Slugs are attracted and fall in and drown. Empty in the morning.

The down side: Using this control on a regular basis will attract more slugs to the area.  They will come from up to 200 yards away!

A Nod to Natural Predators

Ever since I was a little girl I’ve always found lightening bugs delightful.  Who among us has not caught them and put them in a jar on a magic summer evening when we were young.

When I read years ago that the larvae of the lightening bugs destroy slugs, I gained a new appreciation for them and love seeing them in my garden.

Shrews, moles and toads eat slugs.  I still don’t want too many shrews in my garden.  I know they’re there, because I usually catch them in the traps set originally for voles.   I don’t want any moles in the garden because they undermine too much stuff, but they’re there anyway.

Ground beetles and centipedes eat slugs.

Blackbirds and starlings eat slugs. (This may be the only good point for starlings. They are a nuisance otherwise.)

(If you keep chickens and ducks they’ll help keep the slug population down.  Ducks especially love slugs.)

Final Thought

Yes, I don’t know of anyone who “likes” slugs.  They’re creepy and not appealing.  BUT — with all the controls available to us and with exercising due diligence they can be controlled.  Much more so I think than the squash bugs or cucumber beetles!

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Sources:

Diatomaceous Earth (DE) – food grade

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Organic Gardening is easy, effective, efficient — and it’s a lot healthier.

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