I wanted to share this link again. I guess I posted about this in 2020:
Has anyone else tried this besides myself?
I have been loading a spray bottle with a 2% solution of caffeine to help control my massive slug population. I have been happy with the results but was interested in sharing results with others.
no never heard of it or tried it but I see several other sources showing caffeine of 1-2% will kill slugs. Pretty cool will keep it in mind if I ever have issues with them.
Definitely better in the garden than spraying salt water lol
It is indeed toxic to everything, including humans in excessive amounts. Just don’t take too much.
Interesting.
Are you using it at the 2% rate?
Assuming you using powder mixed with water? Where / what are you getting?
Any adverse effects?
Household cleaning ammonia has been my solution. I learned it from an old mentor and friend, whom has left us 10 years ago.
Basically, measure a shot glass of household cleaning ammonia into a 500ml spray bottle.
Then go out when it raining (when slugs are out) or an hour after sundown. That’s when they seem most active here. Then just squirt them.
They act like you hit them with napalm. They die and melt like the wicked slug of the west. Even in the rain. No sloughing off the salt and crawling away or using rain for a saving rinse. Sluggo becomes brown goo in 3 days of Seattle rain and the slugs pass on it then. Also, baby slugs rarely go for it.
Try ammonia, lemon scented hurts nothing and is often all I can find. 2.99$ on the grocery store shelf for a half gallon jug.
Best part is the ammonia spray is harmless to plants. It oxidizes down to nitrate and acts like a foliar N boost.
The only warning is photosensitivity. Do not spray ammonia in bright sunlight. The leaves will not thank you.
I put a plastic container (like a jello shot cup) with about 1/2" of beer in each 5 x 7 bed. If I start seeing wholes in leaves or other items being eaten i do it again. I typically try to do this when it isn’t going to rain for a few days. I put the rim of the plastic cup level with the dirt/mulch and make sure that my irrigation doesn’t water it down. I get snails, slugs, and other little creatures that drown in the cup. I’ll do this before I plant out a new bed or when I see creatures that eat my plants crawling around. If I forget to do this and it gets bad, I will sometimes augment with BT.
Are you using it at the 2% rate?
Assuming you using powder mixed with water? Where / what are you getting?
Yes, I bought the caffeine powder a few years ago. I mix 1 tsp powder to 1 cup water. Heating it helps dissolve quicker.
Any adverse effects?
None that i have seen. I am tempted to try it with a blend of caffeine / ammonia, now.
Ahh, I looked up a few places to get powdered caffeine and if you can find someplace that will sell you without a lab license or business it seems pretty expensive for the treatment. 2 gallons of water would need just under 77 grams for 2% which isn’t inexpensive. And according to the article in order to saturate the soil, if you’ve got a decent size garden, you’re gonna a lot need more than that.
Hello, Thanks for sharing the caffeine tip for slugs. I totally agree with Noddykitty on the household ammonia. Have been using it for several years with gr8 results. You only need a tiny spritz and boom they are gone. Every so often in warm weather I go on a slug search…looking for their clear sticky trails. My slug population is way reduced. Good growing in 2025. Randy/GA
It’s neat to know that caffeine and particularily ammonia work on slugs. Good backup solutions.
Is there a reason to not want to just use sluggo, though? Sluggo is cheap, effective, quick to apply, and labeled organic. I don’t have to spend an hour after dark hunting for slugs to spray, where I’ll only ever discover a small percentage of them.
Ammonia is even cheaper. Pump sprayer can do a good sized lot. And it works in the rain. Just mist the areas they hide and they are toast. No need to hunt them. If they contact the wet ammonia on a quick pass it kills them.
Sluggo has gone up a lot since I bought my house. Ammonia has not. But mostly the baby slugs completely ignore the Sluggo. Like make a double thick Sluggo line and they go over it and onto all your veggie starts and greens. And strawberries,
Also, here in Seattle the high RH from the coastal onshore flow makes morning dew almost every day. Like it rained dew. And Sluggo goes moldy faster than organic gluten free bread does. Then the big slugs skip it too.
The big ones aren’t the problem. It’s the armies of baby ones that hatch out of the soil. They can stay dormant for years and hatch out when conditions are right. Like when I plant my veggies. Like the eggs on Aliens movie sensing humans. The slugs sense my seedlings I have seen my corn and pumpkin sprouts so covered w baby slugs from my green belt, you cannot see green. Just 1-2mm hoards of hungry hatchling baby slugs
One or two bed misting a week at seed sow is way easier than checking if the Sluggo had gone moldy again on all 4 sides of my beds. And the plants seem to dig the nitrogen boost. They all seem a big greener after, or at least I think so and there are no slugs to be seen.
It boils down to its far superior to Sluggo in my pnw coastal climate. Even if it were more money than the Sluggo. Used the Sluggo for at least a decade so I have lots of first hand data.
Wow, sounds like your slug issue is on a whole different level out there!
We have plenty here, but it seems a sprinkling of sluggo in the garden a few times a summer sets their numbers back enough to not be a major issue. I’m still using the same $15 shaker bottle from last year. I usually put it down after a rain when the forecast is dry for a few days, so the pellets stick around for a bit.
