Answer: There are many ways to fight slug invasions. A series of shallow dishes filled with beer or decaying fruit, such as banana peels, are good. Set the dishes at ground level so the slugs are not challenged to get in them. This is probably the most effective. With the beer, the slugs drown and have a happy death. With the decaying fruit, they think they have found slug heaven and congregate in large numbers. The beer trap kills them, while the fruit just traps them. Diatomaceous earth spread in 1/2-inch bands around plants will do them in by lacerating their soft body tissue. Wood ash and hydrated lime (handle with gloves and don't inhale!) spread around garden plants will discourage slug activity. Both materials cause dehydration and burning sensations on their soft tissue. Finally, the best way to control them is to alter their environment. Slugs like cool, dark and moist locations. Prune, replant or do whatever you can to dry and heat up the location where they seem to be most pesky. Persistence is necessary to win the battle. You might use one of the iron based slug baits (such as Sluggo) if you don't want to deal with trapping the critters. Sluggo is safe for wildlife, pets and humans and won't harm your tomato plants. A final note of caution - I would stay away from planting mint in the garden. It is extremely invasive and it won't deter slugs. If you want to grow mint, grow it in a container.
Best wishes with your garden!
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