How big are those pieces of snail bait? The stuff I use is pelleted, and I sprinkle it all around, not just a few pieces near a plant.

It is pellets. What I meant was I literally took 4 pellets and hand placed around the base if each tiny seedling so it was impossible for a slug to get to the plant without passing bait. I do also "sow" all over. My goal with this was I heard slugs really like the bait, so they hit that before plant. I also do this where I knw seedlings are about to emerge.

I prefer just sprinkling the bait a bit further away in a circle around the plants/seeded area - it does attract them, so right up next to the plant doesn't seem like a good idea to me, since it's not going to kill them immediately.

I was thinking about that for next time. I do agree with that idea.

Used coffee grounds and/or barn lime from TSC work for this war with slugs on my veggy beds. I just surround plants with it. Slugs dont like when these crumbles stack to their body, I guess. It is safe, almost free, and it works. (50lb of burn lime ~4$ ) ( earth worms love coffee grounds and fertilize dirt around the plant)

Coffee grounds do not work with my slugs and snails. Lime will affect the pH of the soil. I wouldn't recommend either.

But, but, caffeine poisoning?

https://extension.oregonstate.edu/news/used-appropriately-coffee-grounds-improve-soil-kill-slugs

I didn't see dead slugs , I saw, that after coffee grounds, my seedlings finally survive. Then i've read about burn lime to save hostas if circle them by lime. It works . I live on east coast, our soil is acid, we need to fight for normal ph anyway regularly. So, in my case both bring only benefits. My property also located in forest, it is very humid and warm, i would name it as slugs' heaven.

These guys laugh at coffee grounds, lime, egg shells, sand, everything except pellets and my boot.

Spraying coffee on foliage is useless in a wet climate. When the gastropods are active, ie in rain, the coffee washes off.

Well, the story is that dilute coffee applied to the soil does the trick. Not coffee applied to foliage. Rain just makes it a little more dilute. But I don't have slugs or snails, so I'm just repeating what I wish I had known when I lived in the PNW.

Spraying the soil sounds sounds even more useless. As you say, the coffee would be even more dilute.

I'm just wondering where the percentages for a coffee soil drench are coming from in that Oregon University Extension article. Based on a quick web search, an 8 ounce cup of coffee contains up to around 120mg of coffee and 8 ounces of water weighs 226,796mg. Therefore, a cup of coffee contains up to 0.0005% caffeine. Yet they are saying that 1 part water to 2 parts brewed coffee kills slugs while also saying that the solution needs to be 1-2% caffeine? Brewed coffee by itself doesn't have that much so how strong are they brewing this coffee and/or how much coffee is being applied per square foot of soil? And what affect does this amount of caffeine have on other soil microbes and inhabitants?

Rodney

Escargot is really tasty. You gather them up and stick them in a bucket with a screen lid with some tastier food (herbs are a good choice) for a few days, then you remove the food for another day or two, so they can poop everything out. Then you cook them with garlic. Delicious. A gourmet treat.

(Like most meats, you need to cook them to a certain temperature to be safe, in the case of snails, 165F)

I put used coffee GROUNDS aka crumbles/cornmeal size particles. Not liquid. They are sticky. Slugs don't like them on their body. Crumbles of burn lime do the same. Powder or pelletized lime for soil may not do the trick. I didn't try them for slugs.

Pavlis has debunked the slugs and coffee grounds idea. Of course, caffeine is pretty soluble, so used coffee grounds won't have much in them.

https://www.gardenmyths.com/getting-rid-slugs-coffee-grounds/

But there are other many other coffee-kills-slugs enthusiasts, including a real research paper.

https://www.nature.com/articles/417915a

These researchers did it with 2% caffeine, like the OSU folks. Sadly, though, there were no references to brewed coffee in this paper. They say (I can download the paper) "We do not know how caffeine kills slugs and snails. Physiological studies of mollusc neurons indicate that it releases calcium from internal stores, thereby increasing the duration of action-potential plateaus. We found that large slugs placed on loose soil and sprayed with a 1 or 2% solution of caffeine responded with uncoordinated writhing; the only survivors were the few that were able to burrow into the soil soon after treatment. We anticipate that, in an agricultural environment, slugs and snails will be more susceptible to contact poisoning from caffeine than other animals such as arthropods. This is because caffeine is highly soluble in water, an important component of the mucus produced by the locomotive 'foot' of molluscs."

That being said, the caffeine content of roasted beans is indeed about 2%. Once you drip it, it's all in your cup. This may be what the OSU folks intended to mean.

In 25 years I've only seen a couple of snails/slugs in my garden so can't contribute much on preventing them. But what I do know is coffee grounds not composted are known to cause phytotoxicity from phytotoxins such as caffeine, tannins and polyphenols that inhibit plant growth. It can also cause Nitrogen immobilization with or without additional nitrogen fertilizer, and why is unknown. Composting breaks down the phytotoxins and therefore a compost pile is the best place for it, and not on or around your plants as a fertilizer.

What is interesting about spent coffee grounds is it's ability as an effective chelating agent with metals (K, Mg, Zn, Cu, Fe) and will hold them in the soil, along with decreasing soil drainage. So if it wasn't for the phytotoxins It would make a darn good amendment in the soil.

The caffeine is what kills snails/slugs and all they need to do as pass over the spent coffee grounds and take up the caffeine through their pseudopod, but it takes more than a 0.1% concentration to run off the snail and at least 1% to actually kill it. (they have little heart attacks). But spraying a concentration of caffeine over 0.1% on your plant will slow down and stop the formation of roots, shoot growth and cause plant tissue to die, so I wouldn't recommend it.

But spent coffee grounds on the top the soil will work because the coffee still contains 1% to 2% caffeine, but won't work long. Caffeine breaks down exposed to UV light and in as little as 3 hours. It would take a daily dosage to have any effect on snail/slug populations. So Snail and slug bait is really the only reliable way to get those buggers.

The Nature research article on this also says ..

"In preliminary trials, we found that 2% caffeine does not damage the foliage of Dracaena, Anthurium, palms or orchids, but that it causes leaf yellowing on ferns, bromeliads and lettuce. This damage could be ameliorated by mixing caffeine with an appropriate agricultural polymer, which could also increase the water resistance of spray residues."

So, in general, spraying caffeine on your plants isn't smart. But that wasn't the recipe for killing slugs.

Unlike caffeine, metaldehyde is somewhat toxic to humans. Iron phosphate, on the other hand, is pretty benign to humans. The latter will kill worms, though. Curiously, caffeine actually increases the lifetime of some worms, though may decrease the size and interfere with reproduction.

Yep, metaldehyde kills everything from birds to fish and I don't think I'd use it. Iron Phosphate is the way to go. You can also make your own bait using 1% to 2% Iron Phosphate and a mix of yeast, flour and water like you were making bread. Slugs/snails love it and are drawn to it by the yeast. If you can find beer without the yeast filtered out it will work too, just spike it with the Iron. Iron Sulfate will also work if you don't have any Iron phosphate, it's the Iron that does the work.

One could also spray the base of target plants snails/slugs feed on with a concentration of 3 tablespoons per gallon of water. It won't work on dirt, once the Iron sulfate hits the dirt it changes to hydrous iron oxide and won't work so it needs to be on something else.

When I mentioned pellets I didn't mean Metaldehyde. They're illegal here.

ETA just found this little chap in the compost pot. Must have come in with some vegetables from the garden. It's spent the night in there with a quantity of coffee grounds and seems fine. I'll keep an eye on it and see if it succumbs later.

Again, used coffee grounds have almost NO caffeine. Caffeine is pretty soluble, and it's all been leached into your cup. To the extent that people might say that coffee grounds kill slugs, it sure isn't because of caffeine.

I'm referring to people promoting the idea that they won't crawl across coffee grounds.

Was the coffee grounds sitting out in the direct sunlight? Like I said earlier, the coffee grounds will have 1% to 2% Caffeine in it and enough to give the slug a heart attack, but UV light will degrade Caffeine quickly.

It's a good experiment, if it wasn't in sunlight long the snail should die in less then 2 days. If the Caffeine was destroyed by UV light you have a new pet.

That's FRESH coffee grounds. Used coffee grounds will have almost no caffeine. Who's going to dump fresh coffee grounds on the soil? That a really expensive way to do away with slugs!

FWIW, I used to have a really bad slug problem - probably because I used logs to surround my veggie beds. They were really huge ones too - up to 3 inches or more when stretched out.

Regularly using the iron phosphate pellets has pretty much eliminated them - and getting rid of the logs helped too 😁

Golly Dan you are right. I checked and my numbers were for fresh coffee grounds. 3mg to 8mg per gram in spent grounds is almost nothing. My percentages needed to kill snails is correct coming from a number of scientific studies so at best spent coffee grounds will give a snail a buzz, or high or whatever coffee does. I don't know because I've never had a cup of coffee in my life, so spent coffee grounds are worthless and should just go in the compost pile.

I can't believe there are so many websites promoting this myth, even the university of Oregon is pro on spent coffee grounds killing snails. Shame on them.

Why is so many "killings" in this topic? I think Gardening is for love to plants and peace with other nature, even it is not so friendly to us from some point of view. I think the topic should be about how to save seedlings from damage but not killing everything around them.

There are different spieces of slugs. some of them are smart and polite enough to not to go thru sharp and stinking crumbles, they just choose to turn and go other direction. Problem solved, everybody is happy.

Some slugs cannot be avoid or killed by anything, even by nuke, Spanish slugs for example, but we dont have them here yet. So , for a while, we could continue to enjoy our gardening.

As a University of Oregon alumnus, I must correct you, That piece is from Oregon State. Go Ducks! But OSU is a good ag school, and I usually trust their work. However, as noted, published research does find that caffeine kills slugs, As to whether coffee grounds do so, that's another matter.

Smart and polite slug? I'd love to meet one!

Have you ever tried Tobacco Dust for Gardening on snails?

Where can I buy it in US? online search shows only India's sellers.

Tobacco dust is indeed understood as an effective molluscicide. It is somewhat toxic, however. Best to avoid breathing it. Tobacco-smoke residue that lingers in house dust (third-hand smoke) is known to be harmful.

Wouldn't Tobacco dust be a potential source for tobacco mosaic virus? What ever, but you can get a pound of shredded tobacco from any tobacco store for $20 and make your own dust. The shreds or dust can be put in a 160 degree oven for as little as 5 minutes and kill any virus. I'd opt for 10 minutes just to be safe. I will defiantly remember this new trick if I ever get snails, but I'll need to figure out how to get the snails to smoke the tobacco.

:))))

The India's sellers say that tobacco powder not just kills snails, bugs, flees, e t.c. , but also it is good fertilizer, and it is organic.

Why it is not in our garden centers then? Some kind of tobacco mafia involved or what?

I think Bonide used to market garden tobacco dust (0,.5% nicotine), but that was taken off the market . I think the EPA cautioned against nicotine products and requested product cancellation in 2007. I am regularly amused when people INSIST on using organic materials when those organic materials are more toxic than a non-organic material.