Cabbage, caulifower and other crucifers seem to attract cutworms. There are thousands of varieties of cutworms that can overwinter in the garden for two years before metamorphizing into a moth. They are tiny, hard to see and often live just below the surface of the soil where they are invisible until you walk out in the morning to see that your cabbage seedlings are either wilting (because they are not yet thoroughly cut through) or lying in a wilted pile with their cut stems clearly exposed.
There are a number of ways to prevent cutworm damage. The first way I ever heard of was to put a collar as a barrier around each seedling of cardboard, tinfoil or other material that went into as well as above the soil. Wood ashes spread around each plant is another kind of barrier, as are cornmeal, coffee grounds, crushed egg shells, or diatomaceous earth. All of these, one way or another will kill the cutworms. I was fascinated to learn that cutworms love cornmeal, but can’t digest it, and kill themselves by gorging.
The Old Farmer’s Almanac and Mother Earth News have more complete information about cutworms and the variety of ways they can be controlled including by importing tachinid flies or trichogramma wasps. Don’t forget to treasure such natural predators as toads, moles and birds.