Agree with the previous posts - the benefits far outweigh the problem. Not only for this year but for the future improvement of the soil. And the slugs can be controlled. Straw has an additional benefit - slugs don't seem to like the sharp edges. I wish it was easier for us to get down here.

Dave

My response to slugs is beer traps. I sink a yogurt container into the soil so it's flush, and fill it with beer (cheap, leftover, whatever). The slugs climb in and drown, and that is that.

I've always used yogurt cups, but some people prefer shallower things, like perhaps a pie plate.

Unfortunately, coffee or caffeine is NOT a slug deterrent. Caffeine DOES have toxic effects on slugs and snails but only small, immature ones, not adults, and they must consume treated foliage before it has any effect, which is hardly a deterrent where young seedlings are involved. And the caffeine must be in suitable concentration - at least 2%, which is well above the amount of caffeine found in all coffee drinks with the exception of espresso. The problem is that this level of caffeine also creates phytotoxic reactions with the plants. So while you may be dispatching at least the younger generation of mollusks by spraying the foliage of seedlings with coffee, it's not of much benefit to the plants if they perish from being devoured so the caffeine will do its work or from their own toxic reactions. And used coffee grounds have no effect. They are neither attractive to slugs to eat and they have no effect on them when they do.

Your best results are going come from manual collection and removal (a very satisfying if messy process) or using a recognized bait or trap.

Thanks for the replies everyone.

I am very familiar with what the "books" say regarding the benefits of mulching, and I have seen some of those benefits over the past few years (with the exception of last year which was record rainfall for past 85 years). I have also seen the damage inflicted by a slug infestation, especially on my lettuce plants (the head lettuce got absolutely shredded). Manual collection is just not really an option this year given the size of the plot.

At the end of last season, I started to experiment with the iron phosphate baits and seemed to have some success. Perhaps I will start with mulch in the pathways and litter the mulch with these baits. Take a wait-and-see approach. If it gets out of hand, I can always remove the mulch n'est pas?

USDA researchers in Hawaii discovered, some years ago, found that spraying plants would deter, and kill, the slugs and snails they had around there and many others of us have since tried spraying cold, caffienated coffee and have seen slugs killed by that spray and have seen them detered from munching on foliage srpayed with that cold, caffeinated coffee. Of course, anyone is free to disregard this research that has been availalble for a number of years.

Here is a link that might be useful: caffeine and slugs

This study was done on tropicals in Hawaii not lettuce in Canada, so results might not be quite the same. And brewing enough strong coffee to treat 1600 sq. ft. on the chance it might help is probabaly as expensive as proven iron phosphate. Coffee washes away easily with rain while iron phosphate stays active for 3 weeks even with rain.

Karen

And lest I be queried as to what I would do...

As much as it pains me to say, I'd use the beer (sob) trap. It seems to be effective and not really costly.

Although I do have fears for all the mayhem that may come about with all the drunk and disorderly critters running about one's garden. All the male slugs will of course think that they are incredible dancers and all the female slugs will be so much more attractive. The debauchery will be astounding.

Lloyd

P.S. I have never seen an actual slug in person.

I have never seen an actual slug in person.

You are quite LUCKY! Ugly...ugly things! If you ever do see one, pour just a bit of salt on it....great fun if you're not squeamish. :-)

Val

"I have never seen an actual slug in person."

Lloyd, I could send you some. I have extra, lol.

I don't know anything about coffee and slugs, but I can attest to success using ammonia spray. I use one part ammonia to 10 parts water in a pressure sprayer. I go on slug patrol early in the morning and just spray away. It doesn't harm the plants at all. I look for places where they congregate, like under rhubarb leaves or anything that lays on the soil. Just lift the leaves up and spray. Where they seem to be causing the most damage, I lay down damp boards or newspaper, then when they gather there I just lift up and spray. I don't know if I'm reducing their numbers, but it satisfies me to watch them die.
I know the beer thing is supposed to work, but it's too time consuming in a large area. I always forget about it and end up with a fermenting mess.
I also sprinkle the slug bait around the plants I really want to protect. I use the stuff that's safe for birds and pets.

As far as mulch goes, for me the worse infestations seem to be in areas where I have a living mulch, sedum for example. It's very difficult to spray under it since it roots along the stems.

Good luck with controlling your slugs. I hate them also.

Where I live, wood lice (sow bugs) are a big problem in mulches. When their numbers get high enough, they *will* consume your tender young plants.
So I don't mulch, but actually... I do. The top inch of soil is a mulch for the soil below. It keeps the sun off and prevents subsoil overheating. It keeps moisture in, as long as the soil-mulch is kept uncompacted. It doesn't contribute organic matter, but I already have a composting program for that. So I figure... why bother adding mulch?
I think I've heard this referred to as a "dust mulch". To work correctly, though, you do need to keep the top inch fluffed up with a hoe.

If slugs are a problem in your area maybe it might be best to grow crops that aren't affected as much by slugs.

With respect to using The Internets to determine whether caffeine is an appropriate or effective slug repellant, The Google doesn't have a 'wisdom' or 'effective research' button.

There is no evidence for the efficacy of caffeine for treatment, control, or repellant properties in northerly latitudes on agricultural crops, despite the confident assertions above (which one notes, is not backed up by personal experience in any case).

I am not against anyone trying it and seeing if it works, but confidently asserting it works is poor advice in my view. Linking to a 2002 press release that repeats the Nature findings is not evidence for efficacy in northerly climes. Come now. Where are the products on the market capturing this efficacy?

Who is going to brew 2% solution and hope it doesn't burn cole or peppers? Someone try this on their garden and let us know. I'll wait.

The basics of non-toxic slug control are well known. Copper, diatomaceous earth, beer traps, egg shells, hand-picking, bait with old flowerpots, habitat reduction (which is inappropriate advice here). Iron phosphate may very well be safe and non-toxic when RTFR and not in high concentrations around dogs, and it is certainly effective. These are long-standing elements of an IPM strategy.

Back when I lived where there were slugs, I used beer traps, old flowerpots, diatomaceous earth, copper strips around pots and along top of raised beds. I particularly enjoyed picking them and throwing them on the house and shoji roof, where the birds would regularly patrol looking for my finds.

Do the mulch. Far, far, far more benefits than not using it. Bait and trap for slugs and feed the appreciative birds from trapped slugs.

Dan

Google doesn't have a 'wisdom' or 'effective research' button.

You obviously have not seen this.

I used to have slugs and snails. We had them twice. The first time (before I moved to the organic program) I applied ammonium sulfate fertilizer. A few bucks will buy you a lifetime supply. If you look at it, it looks like rock salt. It works the same way on snails and slugs, too. They can't budge without contacting salt...and they die. It happened overnight.

I saw them again a few years later right before I changed to an organic program. And then they disappeared by themselves. I also had a resurgence in toads, lizards, geckos, and birds once I quit using -icides. I attribute the control of pests to the organic program.

There are two topics in my comment above: caffeine's efficacy to repel slugs and resultant phytotoxicity, and IPM for slug control.

When we examine the Google Scholar search on caffeine and repellent testing, we find the hits are the 2002 Nature paper and avian repellent. There are no spraying tests done in northerly climes. Not using the crops I named above. Not other crops. Nothing. Note the patent app for granular repellant.

There is no basis for recommending a spray, as I asserted above. There is no evidence for the efficacy of caffeine for treatment, control, or repellant properties in northerly latitudes on agricultural crops, as I asserted above. I am willing to listen to someone who has actually expended effort and themselves, in their garden, spread coffee grounds and found them to be an effective repellent; I am not interested in a link to a press release or to a forum discussion where someone read a press release somewhere that caffeine is a repellent.

Regards,

Dan

Lets see now, Since the original research on using milk as a fungicide was done in Brazil then milk will not work in the USA because the research was not done here. If the USDA did research on something in North Carolina that research could not be applied here in Michigan because it would not work. Since it was found that GE altered Rape seed would pollinate unadulterated Rape seed in Alberta, Canada that means it will not pollinate any Rape seed here.
How provincial that thinking is.

Kimmsr,

There has been no research.

That is the point. I say again: there has been no research on garden crops we grow. Get it?

Do you get the difference between greenhouse plants and totally different kinds of crops out in the open?

So, you can brew your morning brew 5x stronger than normal and go out and spray your garden crops and let us know how it goes. You are confident it works. You do it.

Have fun. Take pictures. Share them with the forum.

Dan

Research findings that show positive results for controlling a pest on one plant in one climate are not generalizable to other plants, climates, soils, conditions, etc. That isn't being provincial; quite the contrary, a disciplined approach to controlling variables is essential to valid research results.

FWIW, I have used coffee grounds around my hostas for several years now. I apply it about 1/4" deep in a 4-5" wide circle around the crown when the shoots immerge in the spring. The grounds are rich in nitrogen and seem to give a boost to the hostas. The grounds also have a rough texture and slugs seem to avoid crawling over them. I think the combination of faster growth and fewer slugs makes a big difference, and I have been really happy with the results. However, I don't think it has anything to do with caffine.

In general, I control slugs in my garden with iron phosphate products like Sluggo. I apply it very sparsely but often, like every week or two, and it works well.

I have sprayed slugs with coffee left over in the morning, that does not happen too often, and I have seen the slugs die after being sprayed directly with the coffee and I have seen slug damage cease on leaves of plants the slugs had chewed on.
Cold, caffienated coffee is a slug deterent when spayed on plant leaves.

Dan: Kimm doesn't show pictures. Of anything. Ever.

Kimm, we'd really like to see some pictures of your compost area, your compost, your soil, your gardens. Show us how an expert does all these things.

{{gwi:269200}}

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Karen

That isn't being provincial; quite the contrary, a disciplined approach to controlling variables is essential to valid research results.

Yes, exactly. The lack of a 'wisdom' button on The Google tends to make scant findings overgeneralizeable.

-----

Kimmsr, since there is no published research on the phytotoxic effects of caffeine on field grown crops, you are the resource.

Please tell the forum which plants yellowed and which didn't, and which plants benefited, as the only trials are greenhouse trials at this point. And they found the efficacy of caffeine at the concentrations you drink was spotty and plants still had damage.

So. Details please, as there is no information out there and you seem to be the sole resource for people to go to. Which plants did you spray, which yellowed and which did not?

Thank you in advance.

Dan

Karen, I was thinking the exact same thing :-)

Kimmsr, by all your descriptions and inferences, you must truly have a "wonder" garden to be so amazingly successful despite the fact that it flies in the face of most accepted and scientifically based garden and soil principles. I too would love to see photos to document this remarkable place. I'm more than a little surprised that such an incredibly successful and productive garden characterized by such unconventional techniques hasn't already shown up on the news and that you are not now currently on the lecture circuit extolling its virtues and your methods for all to benefit.

So what gives?

Not too mention kimmsr keeps calling soil texture...structure in his jar of soil settling method.

Wow. Looks like we should shut down the forums and direct all inquiries to published research papers. It is a good thing our ancestors did not feel this way about anecdotal evidence.

I read the same article when it came out. In fact, I believe I was directed to in on a GW thread. Seeing as "leftover coffee" is a term I don't quite comprehend. (sort of like "old beer" or "too much garlic") I decided to use my coffee grounds instead.

I surrounded my slug-prone plants with a 1" thick ring of coffee grounds and make a point to not let the leaves touch the ground outside the ring. In my experience, it works very well. The grounds must be directly on the ground and not covered with any other mulch. Now, whether the results are due to caffeine, the texture of the grounds, or my overactive imagination, I guess I can't say. It appears to work for me and I have been doing it for years now.

What I do know, is that Mother Earth News is asking readers to try it (specifically on cabbage) and to report their findings. The results will, of course, be anecdotal, but if they are positive, it may prove cause enough to have an "official" study performed.

Kay

Karen, beautiful pictures (nice hummer)!

DW called me an idiot, she said there are lots of slugs in the hosta bed (under air conditioner) in back of the house and if I ever took the time to get down on my knees and weed back there I woulda seen some.

Not quite sure, but I think she was trying to tell me something.

Lloyd

P.S. I don't garden, but I show lots of pictures. :-) Some people tend to ignore me. LOL

What a pretty yard! And we love your pictures.

And if you've never met a slug, go to your hosta bed and meet one. Look for an ugly slimy booger- that's him.

Karen

One thing I would like to see for those using coffee sprayed on the plants is how many scoops and what size of scoop did you use to make the coffee. Also did you make it as a drip, percolated, french press or other method. I drink a lot of different types of coffee and know that how you make it is as important to the strength as how much you use.

Kay, I don't think anyone is objecting to anecdotes. The problem is confusing anecdotes with facts.

What I have said many times before, absolutes are very seldom encountered in the world of gardening and too often we see posters - a few in particular - stating personal experiences or opinion as facts or absolutes. To do so is misleading and inaccurate.

When we advocate unusual approaches or recommend methods that do not have the benefit of science behind them it is irresponsible to state them as fact - as has been seen and demonstrated countless times, what works well in one location for one set of circumstances may not work at all similarly elsewhere. If it the results were that uniform and universally accepted, there would be verifiable documentation to support them. All we need to do is rephrase and condition our responses appropriately and then the information is presented for all to share, if they so desire, but in a far more responsible, less absolute or dogmatic manner.

So rather than stating bluntly "cold, caffienated coffee is a slug deterent when spayed (sic) on plant leaves", for which there is NO scientific evidence to support, wouldn't it be far preferrable and a much more accurate presentation to state "in my garden (or IME), I've found that spraying the plants with cold, caffienated coffee helps to keep slugs under control"?

To present unverifiable and unsubstantiated personal experiences/opinions as fact assumes a degree of authority that is dubious at best and sef-aggrandizing at worst.

Let us note that the person making the caffeine spraying claims is not clarifying their particular technique, or providing additional information on plants, crops, dilution/concentration, time of spraying, nothing.

IME this is a poor sign for credibility of assertions. Especially as the sparse information available out there states there is plant damage associated with spraying, which prompted my clarification requests above.

That is: it is the height of irresponsibility to advocate caffeine spraying without providing caveats. I suspect the lack of experience of the claimant makes caveating difficult, if not impossible.

Dan

Whoa...what a kurfuffle. Here, the coffee used is made in a French press, and it's organic and ground just so...but seein' as how I allow myself only one cup a day any more, there's no way I'm wasting it in the garden. Of course, I'm odd man out on the whole slug issue anyway. My method of slug control? None...nada...nothing.

Well, except for the local toad population.

Yup, folks, you heard it here first. Toads LOVE to EAT slugs. Love love love slugs. So if you have slugs and don't like 'em much, and if you don't want to spend your days brewing coffee or saving up stale beer, garden organically, and get yourself some toads.

Seriously, the former owner here did one thing right, and that was to garden organically for almost 20 years here. What with the pond, the culverts, the high water table, the damp, the sitting water in part of the garden much of the year, the whatever, we have gazillions of frogs and toads. I've seen the toads on the patio, in the grass, in the veg garden, in the beds....

I'm sure we have slugs, too. But as far as I'm concerned, those slugs are TOAD FOOD, so (please don't think me too odd), I leave 'em alone. No stale beer, no diatomaceous earth (which BTW will harm any soft-bodied thing, not just slugs), certainly no organic coffee ground just so for my one cup made in my French press. No nothin'....just a lot of toads.

And seriously again, if I had to make a choice between mulching my plants and having slugs or having no slugs and no mulch, it's no contest....I'd mulch.

I forgot to mention: I never post pictures either. Never. Of course, I don't exactly know how (red face). But I've been under the impression my pics can then be used by this site. Maybe I'm wrong, but....I don't post pictures.

Kimmsr, I am fond of you, and I am a friend.

I'd be delighted to know even one-tenth about gardening as kimmsr does. I'd be delighted to know one-tenth about gardening as most of y'alls do.

I, too, consider kimmsr a friend. He's wrong sometimes but he's still a friend, ;-) After I have done more reading, I have decided that in his and my exchanges on compost, he turned out to be "more right" than I was. Now that I am more enlightened, I often suggest that the routine use of compost on lawns is a good idea. This is in line with kimmsr's program and completely the opposite of what I believed just a few months ago. But I don't give him or any scientific journal (from Russia, dated 1900) credit.

Thanks to kay____h for the reminder that this is not the "scientifically proved" forum. When asked where I have learned what I think I know about gardening, I always explain that it came from the experiential evidence (aka anecdotes) found in these forums. For example, even though the scientific studies for using ordinary corn meal against fungal diseases may never be finished, there are too many people writing in here to say "it works" for me to believe otherwise. I don't know if I was the first to put it together but I am the first one I know who repeatedly pounded the drum on the idea of coupling watering the lawn deeply and infrequently along with mowing at the mower's highest setting to have an incredibly good looking lawn with no weeds. Where did I learn that? Years and years of reading the GW lawns forum and putting two and two together to make four. All the evidence I need is in that forum. I could not even point to 99% of the messages that formed my beliefs but a few stick out in memory. Unfortunately they drifted off the bottom of the list back when Spike owned GW. More recently I see that the water/mowing ideas are showing up in magazines and other websites. That's a good thing. People are getting on the bandwagon. But more to the point (sorry for drifting), I don't think there is any presumption that one person's opinion is fact no matter how forcefully they say it or how often they repeat it. Didn't anyone every tell you to beware of what you read on the Internet?

lynxe, here in Texas the plural of "you" is "y'all." The plural of "y'all" is "all y'all." My family is from PA and the plural of "you" that I've heard most often is "youins."

And one more thing. When one person is dreadfully wrong time and again, you can learn to discount that person's contributions. Now that I have adjusted my thinking I find kimmsr to be correct on everything. I might quibble with his wording but I give him considerable latitude when he presents ideas that differ from my experiences.

No one is asking for scientific "proof" (a misnomer), rather we are asking for any kind of evidence whatsoever. None of it is forthcoming, and none exists. Where are the testimonials from gardeners? Where are the products such as sluguccino or slugeine to spray? Which specific plants react unfavorably to spraying? We don't know.

Maybe, as I wrote above, someone can go out and spray and tell us which plants react unfavorably. That's all we ask, as many of us won't go out and spray plants willy-nilly without knowing the results (the results that apparently no one knows, BTW).

That is: If I lived in a place with slugs, I'd brew up a strong batch if I knew it was safe to plants. But I don't. So we await someone reporting results. And many others are not going to risk their plants either just because someone read something somewhere that tested in a greenhouse, and found yellowing plants at that.

Sheesh. It's not hard. Where are the specifics for what is claimed above? They have been repeatedly asked for but met with silence. We await spraying results from reg'lur folk, sciency folk, farm folk, folk folk. Any old folk.

Who is willing to take the risk and spray various plants and relay results?

Dan

"Where are the testimonials from gardeners?"

"many others of us have since tried spraying cold, caffienated coffee and have seen slugs killed by that spray and have seen them detered from munching on foliage srpayed with that cold, caffeinated coffee."

Well if we're going there...it isn't just about being right or wrong. Anyone who claims they are correct all the time is delusional.

My issue is often with the presentation of what seems to be a fact yet upon doing some research turns out not to be the case. Quite often these "facts" are attributed to other organisations (USDA, Ag schools, CDC, ATTRA, they said, etc etc) without a link to support the attribution. When I have taken the time to research it, I find that sometimes these "facts" are not at all what the organization said or claimed. The "fact" was taken out of context or completely misrepresented. When this happens repetitively, it causes me to question the validity of much the poster has to say even though it might be true. In a nutshell, I won't trust them. I'm not asking them to prove anything scientifically, I would just like to see for myself where they got the information from.

They may be a very good gardener, they may have vast knowledge, they may be very friendly and helpful, they may be a rocket surgeon, but if I can't trust them, all that isn't very useful to me.

People have biases, beliefs and opinions, no problem, just don't present them as if they are the gospel. There are gray areas in almost every situation.

I have my list of people whom I consider to be a VoR, I don't expect all to agree, so be it.

Lloyd

bp, thank you for helping me to illustrate my overarching point perfectly.

The statement upon which you are presumably relying is not based in any fact that a number of us on this thread can verify, thus the length of this thread, the (unanswered) clarifying questions, etc. A Forum search finds the same circumspect thread content, replete with a similar pattern of incorrect information, therefore the insistent clarifications.

Dan

Hollingsworth suggests that in a field situation slugs encountering caffeine are more likely to move to other non-treated plants. In the meantime Louise Simms and Dr Michael Wilson of the University of Aberdeen have investigated caffeine on the basis that it is an Âenvironmentally acceptable alternative to metaldehyde and methiocarb (Simms and Wilson, 2002). Caffeine, a natural product, is classified by the US Food and Drug administration as a GRAS (generally recognised as safe). Simms and Wilson presented new data suggesting that caffeine may be a less effective molluscicide than previously thought [due to the sheer amount needed for treatment at the ag scale and resultant effect on receiving waters -D]. In addition, the product was shown to be toxic to three earthworm species at low doses and some phytotoxicity was observed on the plants. [emphases added]

Boy, it would sure be nice to know on which plants somebody upthread sprays coffee, so we can avoid phytotoxicity. Don't want dead plants, ya know. Suuuure would be nice...

Dan

And I had to chuckle at the last statement in the caffeine chapter from Dans' link;

In their conclusion they suggested that
caffeine has no environmental or efficacy benefits over
metaldehyde and commented that the public perception of
Ânatural products being less detrimental to the environment
than pesticides was not always accurate.

Not always accurate public perceptions, I wonder how those happen!

ROTFLMHO
Lloyd

I'm surprised at the finding that product was shown to be toxic to three earthworm species at low doses . I wonder what those three species are? UCG are a well accepted food source for worm bins. I sprinkle a handful in every once in a while. I only have Eisenia fetida*/Eisenia andreii and Eisenia hortensis in my bin for now, but I'm going to also add some Eudrilus eugeniae, Amynthas gracilus, and Perionyx excavatus.

I agree, pt, that the actual paper has an interesting conclusion.

----- UCG are a well accepted food source for worm bins. I sprinkle a handful in every once in a while.

That's not what we are discussing.

Dan

But rj brings up interesting questions though. Is it because the caffeine has been mostly removed during the brewing process that makes the grounds not so toxic? Is it the type of worm? Or maybe because the caffeine is dissolved in the water making it easier to absorb for the worms? Is it a combination of the level and the speed at which it is consumed? Other reasons?

Interesting.

Lloyd

Because caffeine is soluble in water, the brewing process extracts most of it, leaving the used grounds with very low levels of caffeine compared to the brew itself. Soaking the beans prior to roasting is one of the chemical-free ways coffee is DEcaffeinated. One article reports a caffeine level in used grounds of .13% - likely nowhere near a sufficient concentration to kill worms OR deter slugs :-) This is a significant difference from the 2% caffeine referenced in the Hollingsworth study.

My focus is on the phytotoxicity from spraying, and I am still awaiting additional input from members who claim efficacy.

Dan

coffe grind is good for compost pile but not a good mulch.

things like pine needles, semi-composted or brown leaves, straw(without seeds), dryed grass clippings,...
make good mulch.
Coffee grind in no different fron soil.

This link is to a USDA ARS article about caffeine and slugs, however it is unlikely to cahnge some peoples minds.

Here is a link that might be useful: USDA ARS article

Kimmsr, again, to repeat, reiterating:

the question is about your claims about your experience, which don't seem to be forthcoming. I repeat what I wrote above, that links to the Nature article don't interest me.

This continuing pattern reinforces suspicions that caffeine sprays haven't been done on personal gardens & recommending them is poor advice.

Dan