Forget the Sluggo at the bottom of your concoction. Slugs, if they come to feast, will be on the surface.

But Jean, slugs live in dark moist places:
Where do slugs live - Slugs thrive in a high moisture environment. When considering where do slugs live in my garden, you should look far anywhere that moisture may be retained. Common places to find slugs will be under pots and containers, under mulch, under boards, under rocks and deep in overgrown vegetation.

Slugs may eat garden vegetables by crawling on top of mulch to get to them, and it may be that they'd eat the Sluggo if it's on top, but I know they'd be under the mulch, as well.

So that was my thinking, and why I was wondering if Sluggo harms earthworms, no matter where it's applied actually.

Google 'iron phosphate earthworm' for more info, but the EPA and independent tests have shown iron phosphate baits pretty harmless to worms when used as directed. In one study the worms lost weight, but had lower mortality. Evidently those were some fat worms ;)

JAG

Thanks for the Google suggestion. I posted the question because I couldn't find anything Googling under "Sluggo earthworms". So now I may have seen that study you referred to and it said for this study the application rate was 8 times the recommended amount. I'm glad to know that with recommended amounts it's safe to use.

You wrote "slugs live in dark moist places"

Yes, I understand that.

But not at the bottom of a lasagne bed, or whatever it is that you're intending to build.

jean is correct. The only way you are going to have slugs in there is if you leave the cardboard for weeks. If you put cardboard down and start making a lasagna bed, you won't have slugs living there. They will commute, of course, to their jobs on the melons from elsewhere.

Dan

jean & dan

While where slugs hang out in a lasagna garden is interesting, I don't have a lasagna garden and don't plan to continue my beds using that method. I didn't ask about a lasagna bed in the opening post, just whether Sluggo would kill earthworms, but it got added into the stew anyway.

As I've done for years, my irrigation system is laid on top of the compost existing from the prior year and the cardboard is placed on top of that. Leaves are placed on top of the cardboard for aesthetic reasons, eventually to become compost, and to keep the cardboard damp and attractive to earthworms. Unless it's right after rain, the leaves stay pretty dry on top, and I've never seen a slug on the upper leaves, just under the cardboard and eventually at the boundary of the cardboard and the leaves.

For those of you who answered the question about whether Sluggo kills earthworms, thanks. That's what I wanted to know.

Here is a scientific study that says that iron phosphate itself didn't seem to harm earthworms, but Sluggo did.

Try ducks, mine love slugs!

Garden Web!!! Please let others know it will kill worms!!! A very well hid secret that it is not telling anyone!- on the package! I think that stinks!!! I am contacting the companies that sell this product "as safe for pets!" and / let them know they a are sneaky devils! I makes me so mad that they hide the fact that it kills garden worms!! I am also going to other garden sights to tell others!

This study done by people at Ohio State University indicates there was no significant harm done to earthworms by Iron Phopspahte slug baits.

Here is a link that might be useful: About Slug Baits

I don't think they hurt them because I've used iron phosphate baits for many years & still have lots of worms. The red wigglers that live in compost don't continue to live in the garden once you spread the compost because they no longer have the uncomposted food. The burrowing earthworms will.

anney, I put collapsed boxes down to kill annual grasses & weeds. The Bahia grass will grow 20 feet to fine sun light.
I check weekly to see what is dead. I found spiders, crickets
& other bugs in compost, but NO slugs or snails, not termites.

I think someone needs to reread that Ohio State report a little bit more carefully:

These data together provide clear evidence that molluscicides containing iron phosphate combined with either EDTA or EDDS can have adverse effects on earthworm activity or growth and may possibly be toxic to them.

FWIW, it is the chelating agent EDTA in Sluggo that creates any toxicity. Otherwise consumption of the iron phosphate in this and other similar molluscicides would be as "safe" and non-offensive for slugs and snails as it supposedly is for any other creatures.

This product should be used with caution around pets and kids as iron poisoning is a distinct possibiity if consumed in quantity (i.e., keep bags/containers secure and out of reach).

Thanks for asking thecwuestion.