A large number of garden pests are nocturnal. I took these photos in my garden in the Wallingford neighborhood of Seattle around midnight this spring.
If you’re wondering what is eating your plants try going out with a flashlight at least an hour after dark. You may be surprised by what you find. Those notches on your Rhododendron leaves? That may be from an adult root weevil, which feeds at night. Seedlings in your garden full of holes and covered with slime trails? Probably slugs or snails. With just A few nights of collecting it’s possible to really diminish the population of some pests such as the cutworms pictured- especially in smaller urban gardens.
If you’re interested in identifying pests you find, I recommend checking out the book Garden Insects of North America by Whitney Crenshaw.