I have a small garden in my backyard (a 4x4 "square foot" garden). It has a variety of different plants in it. Recently I tried to grow melons in it (watermelons and cantaloupes). But, shortly after it grows a couple leaves I return the next day to find the leaves torn off the stem of the plant. Just the stem is left and torn pieces of the leaves. My other plants don't have this problem, it's just the melons. I replanted, and the same thing happened again. What could be doing this and how can I defend against it?
It could be snails or slugs. You won't see them during the day but if you can go out after dark with a flash light you may be able to find the culprit (snails, slugs, rabbits, squirrels). You can also put a night vision camera outside if you want to see what is visiting you at night. You can also look below the leaves to see if you can spot any insects (caterpillars) that may be feeding on these leaves. These are all issues I have seen in my garden at various points in time.