Snails and ammonia

11 years ago


I need some urgent advise on controlling snails.

It started last year, but now parts of my garden are infested with grapevine snails. The adults are close to an inch across. I've catched about 700 of them this year, but there are hundreds of them left. Last year, all that was left of an giant clump of H. 'Fried Green Tomatoes' were some leaf stalks with a couple of threads, the remains of the veins.

Does spraying with an ammonia solution help, or does the shell protect them ?



PS: there's one good thing about it: I haven't seen a single slug this year.

Comments (13)

  • hostasformez4
    11 years ago

    Tthe full slug season is not here yet in Illinois USA.

    I personally don't have snails in my garden but I do know that the ammonia/water mix will stop slugs in their tracks!
    You have to repeat at least once a week starting early whenin the growing seasom when the hosta eyes are starting to emerge. Then as often as you you feel the need.

    With snails I think you would need to spray when they are active as they can draw into their shell for protection, but as long as they crawl through the solution I think it would kill them if it is fresh

    I'm sure others will respond to your question and give you more infornation.


    PS: Some people even go out at night and spray when the snails/slugs are active.

  • ken_adrian Adrian MI cold Z5
    11 years ago

    there is a FAQ on the battle against slugs...

    there is no difference between 10% vinegar or ammonia... whichever is cheaper ...

    no background in snails.. so you will be the new leader in that aspect


  • rob_sneyers
    Original Author
    11 years ago

    Tonight I tried the ammonia method on snails. Having tried numerous snail- and slug fighting techniques, I was a bit sceptical.

    But it works...boy does it work.
    Every snail that gets hit is instantly tranformed into yellow-green slime. They don't even have the time to let go of the leaf and drop.

    No more freeloaders on my leaves.

    Greetings from the Hosta Mill,


  • sandy68
    11 years ago

    does the amonia hurt the hostas?

  • rob_sneyers
    Original Author
    11 years ago

    Hello Sandy,

    No, it doesn't hurt them at all.
    It's rapidly broken down to nitrogen, a nutrient for plants.



  • shade_tolerant
    11 years ago

    As long as the ammonia is mixed properly with water, generally 10-15% ammonia, the rest water.

  • rob_sneyers
    Original Author
    11 years ago

    I've sprayed almost the entire garden 3 times now.
    First time ammonia, 1 part on 10 parts of water;
    Second time, vinegar, 1 part on 10 parts of water;
    Third time ammonia, 1 part on 16 parts of water.

    My conclusion is ammonia works best, and with a leafed out plants the 1/16 solution is plenty strong.
    The vinegar didn't work as well, and the stronger ammonia solution did some (minor) damage to a few leaves.

    If you're having serious slug and snail problems, like I did, the ammonia treatment is the way to go. My 1/4 acre garden was completely infested. I've seen plants that were really covered with snails and slugs, turning it into gruyere cheese in a matter of hours (there seem to be a number of cultivars that are irresistable to snails). Uptil now, I've killed (est.) somewhere between 3000 and 4000 gastropodes, mostly snails, most of them last 2 weeks.
    Last night, middle of the night, I made an inspection tour of the garden, and did not see a single slug or snail. This morning I saw just one.
    I'm planning on doing one more spraying at the end of the week. Later on I'll keep spraying once every two weeks, just to keep everything under control. There must still be lots of eggs waiting to hatch.

  • bettylu_zone6a
    11 years ago

    I finally did it! My neighbors must really think I am crazy now - I took a flashlight and a cup of ammonia/water mixture to drop them into and went slug hunting!!

    I could not find a spray bottle to use and wasn't sure of the proportion and I simply had to do SOMETHING... We had a tiny bit of rain this evening and the tops of all the leaves were wet - so I found most of them on the tops of the leaves, rather than underneath. The only thing is, you all talk about how BIG the slugs are, and most of the ones I found were REALLY tiny, like the dot of a felt tip pen or, when stretched out, as thin as a pencil line. Not easy to see, especially at night, with a flashlight! I only saw maybe 5 or six that were an inch or so long. Those tiny mouths still manage to make unsightly little holes all over my hosta, though.

    I probably only killed about 30-40, but fewer slugs to lay eggs and eat teeny-tiny holes in my Hosta is still great! Tomorrow I am going to look for/or buy a spray bottle so I can cover more territory without straining my eyes to actually see the little slimers.

    I do have a question, though... do you just spray the hosta (top and bottom of leaves & stems) or do you spray the ground all around too? I don't use actual mulch, only what ground up leaves are left from last fall, but there is still some small leaf pieces that slugs could hide under. Since I am (obviously) a night person, I don't mind doing this for as long as it takes, I just want to be sure I am using the ammonia in the most effective way.

    It is great to have a weapon that actually works against the slugs and won't hurt the hosta!


  • mac_skicanadamag_com
    10 years ago

    Yes, diluted ammonia works on adults slugs and snails but it's best for killing larvae in the soil. The time to do this is in early spring just as shoots are starting to break the soil surface. The dilution ratio is debatable but you should spread it anywhere slugs and snails appear in the spring and summer (soil and lawns). If your neighbours aren't following suit, you'll have to treat your soil again in two months because the slugs and snail will just migrate but if you treat later in the spring, you'll need to rinse leaves off with fresh water or you'll burn them. The ammonia quickly turns to nitrogen so the plants love it but like I said, it's too strong for the foliage usually. Individually treating adult slugs and snails must be painstakingly slow... And beer baths don't work -- the dog keeps drinking the beer! laugh.

  • in ny zone5
    10 years ago

    mac, your dog probably sees you drinking beer, so he thinks he should have some of that stuff too.

  • gayle0000
    10 years ago

    Another thing to remember is the slugs will die when they have contact with the killing solution. If they are hiding on undersides of mulch or other obstructions and don't get hit with the spray, they will live to tell their friends.

    Back in the day, I used to spray, fluff mulch, spray, repeat. It seemed like it never ended.

    Keep this in mind when you have deeper areas of mulch or interesting places they can hide on undersides. I'm not a "drencher", and I'm a single parent with a small kid. Don't have the free time to hunt on slug time.

    I love to spray...especially after rains when it's super-moist and the slugs are out, but have learned that using slug baits is pretty key to controlling the population when my time isn't flexible.

    Just throwing that in.

  • grumpygardenguy
    10 years ago

    OK snails, GODs way of saying "Hey anyone can make a mistake". NO one ever said there has to be a good reason for anything, or that life is easy. SO goes the gardners plight. You can use the Little Black claymation figure Sluggo, or for better results the snail bait. The natural solution is cheaper and wroks as well , but, requires more man hours. Best to use at night or early morning as delicate hosta(ok may be an oxymoron)leaves can burn with just water on a summer afternoon if just watered at the high sun period, much less having amonia included. I have a bit of a mean streak and for those snails on concrete i use salt, just to watch them shrink and if you listen very closely SHRIEK! THey do tend to slime out so a messy tactic, but if you want to revel in their death, then salt is just plain fun in a box. Not sure, but maybe just maybe could collect them all, box them up and sell to the French as a salty snackfood.