Question
QUESTION: Hi, I've just begun vegetable/herb gardening about 2 months ago and am trying to grow as organically as I can.  I'm having problems with slugs and read that lava rocks could deter them so I had bought black cinders since they were actually mini lava rocks.  However, they weren't as abrasive as I thought and one night I did see a small slug on top of one of the cinders (though it didn't get very far to the vegetable and was just sitting there).  Therefore, I'm thinking about buying sandpaper rolls.  I plan to fit the sandpaper around my pots to deter the slugs.  I've read somewhere online that any grit is fine to use but do you know if there is a specific grade that's most effective against slugs?

ANSWER: I don't think sandpaper will deter slugs, but you can try it.  The only thing that deters them is rock salt. If you are growing plants in containers, I would pick some area like a patio, set your pots on it and sprinkle rock salt on the ground around the pots on the ground.  I can guarantee you that you will not have a slug cross a salt barrier. You just have to keep it up.   Just be careful not to salt any area you wish to grow anything in, as it will affect the soil.  

We had a two acre garden that we salt lined the perimeter of, and had a slug free garden. (We made a four inch row of sawdust all around the garden fence, added a 1x4 "roof" a few inches above the sawdust, made a trench, and laid in a row of rock salt. Once the slugs were out of the inside of the garden, it was slug free.)

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QUESTION: Rock salts would last longer than table salt so that sounds like a good idea.  As I further researched the internet, it didn't seem anyone tried sandpaper and it was only a suggested technique so I didn't try it.  I did buy sand since some people said it worked for them when dry so I spread them around the pots.  I hope this works or at least slows the slugs down, but it's great since I can use the rock salts on top of the sand if the slugs are getting out of hand.

I was wondering if I could get your take on Sluggo and its effect on the environment.  I know it's quite popular among gardeners since it says it's organic, but I'm still leery since I've read in some forums that it contains EDTA.

Answer
Well, we conducted a test by putting slugs in the center of a large sheet of plywood.  Around them we had circular layers of every slug deterrent we could find..... they crossed all barriers except the salt.  We did not try sandpaper.  As for any other, like Sluggo, ..."a blend of an iron phosphate active ingredient, originating from soil, with slug and snail bait additives..."  I could not find anything saying it was "organically approved for garden use".... the phosphate would be very acidic, but what are the additives?  I would stick with salt, or if sandpaper works, great!