Sowbugs prefer moist locations and are usually found underneath objects on damp ground. They also like vegetation and can be found underneath all kinds of debris. They are most active at night and feed mainly on decaying vegetable matter.
Sowbugs can feed on seedlings, lower leaves, new roots, and fruits or vegetables lying directly on the soil or near a damp soil surface.
You can limit moisture or excessive vegetable matter in your garden. Also, lining your plant beds with black plastic will help minimize them. They don't like the heat of the black lining.