I left the lettuce in there all day, and when I got home from work it was all eaten and torn up. I still have yet to see a snail. Although, since the lettuce was in there, the other plants appear untouched. I think I found a solution to my problem: Lettuce! I don't have to trash Spot after all! 
On snails: how small can they be? If what I'm seeing truly are snail tracks, they're the tiniest snails on the planet. The tracks almost look like someone took a sharpened pencil tip and dragged it through the moisture.
I need some kind of surveillance camera.

On snails: how small can they be? If what I'm seeing truly are snail tracks, they're the tiniest snails on the planet. The tracks almost look like someone took a sharpened pencil tip and dragged it through the moisture.
I need some kind of surveillance camera.
