So if you notice burned leaf edges and tips and yellowing of your plants' leaves, you may want to lay off the Epsom salts and do a soil test. These symptoms may indicate a salt buildup. Ann Stanger of Virginia makes a slug deterrent from eggshells. She simply crushes the shells into rough chips and spreads them around the plants. The soft-bodied slugs won't crawl over the sharp shell chips.
Eggshells add calcium to the soil.
Plus, they contribute some nitrogen and trace minerals. If slugs are munching on seedlings, try a little sandpaper. Cut a piece into a circle a few inches wide and snip a hole in the middle. Slip the sprout through the hole and lay the sandpaper flat on the soil. Slugs will avoid the rough-textured paper.