Something you will discover when growing vegetables is that there are a lot of things out there that find them yummy. Slugs, for example. The slugs in my garden seem to especially like the heading type of asian cabbages (also known as hakusai, napa, or nappa), but they also chew on other vegetables. Last year, they wiped out some newly transplanted pepper seedlings and made a lot of cabbage unusable.
There are ways to combat the slugs. Ducks and toads are said to eat slugs without causing damage to the garden. Unfortunately, these animals don’t often visit my garden. Saucers of beer are supposed to attract slugs, which then drown in the beer. This hasn’t worked for me, however.
Slug bait does seem to get the job done eventually. You may have seen what looks like white pills in my recent pictures of the garden, such as this one of some chard:
This is actually the slug bait, which contains something to attract the slugs (usually wheat or barley cereal) and about 1% iron phosphate to kill them. After the slugs eat it, they are supposed to lose their appetite and eventually die. The bait is said to be safe for children and pets; my cat has eaten it and come to no apparent harm. The bait eventually breaks down and enters the soil, where it acts as a fertilizer. This year, I am spreading it in every garden bed as soon as I plant, and around the beds as well.
UPDATE: When I ran out of slug bait and went to buy more, I couldn’t find any that listed iron phosphate as the active ingredient. Instead, I bought some with sodium ferric (iron3+) EDTA. From what I have read, this is iron phosphate with the chelating agent, EDTA, added to it. This should work in the same way, but it has been found to be toxic to earthworms and possibly to animals and humans. It is not recommended for organic gardeners.
You can learn more about slugs at the Weekend Gardener website.