So last Saturday I brought some plastic noodle soup bowls to be used for cutworm collars, intending to cut out the the bottoms to create plastic collars. However, I was advised that cutworms collars are needed when the seedlings are fragile, so I didn’t install them. Later, it occurred to me that since this is an educational garden, I should install them anyways (as a conversation piece). It turns out I didn’t have enough soup bowls, so we installed them on some of the cabbage, broccoli, and cauliflower plants, particularly the more struggling ones. As a plus, it was pointed out that the collars help to water those particular plants by cupping the water.
I also did a websearch, and found this nice article on cutworms. As far as our gardening is concerned, I think these are the basics on cutworms. They are spring pests, eating the stem of seedlings only at its base. Since that "cuts" the seedling down (hence the name), the plant is destroyed, and since that’s all they eat before going to the next, they can wreak considerable damage to a garden. Because they dwell close to the surface, collars only need to be pushed a few cm into the soil to stop them. I was surprised to learn that one can even use cardboard collars. They will be a threat to us through May and possibly early June. And the sunflowers we’ve planted in the corners will be a magnet (which we should check periodically to find new cutworms).