Barriers are simple to use, and many are easy to make yourself. Cutworms are one kind of pest you can stop with a barrier. Cutworms are dull gray, brown, or black, and may be striped or spotted. They are stout, soft-bodied and smooth, and up to 1 and 1/4 inches long. They curl up tightly when disturbed. Cutworms literally cut off plants above, at, or below the soil surface. Some cutworms feed on leaves, buds, or fruits. Others feed on the underground portions of plants. Early season plantings are especially delicious to cutworms. Cutworms love tomato, pepper, cabbage, pea, bean and squash plants.

An effective physical barrier to prevent cutworm damage is a stiff 3 inch cardboard collar around the stems; allow it to extend about 1 inch into the soil and protrude 2 inches above the soil; clear the stem by about 1/2 inch.

Rowcovers are typically made out of a fabric that allows both water and light through but protects crops from insect pests and frost. They can enhance yields of some crops, while producing an early harvest on others. They may offer a few degrees of frost protection, and when properly used, they can effectively block the feeding activity of some insects.

Rotate the location of crops that attract insect pests that overwinter in the soil. For row covers to be effective barriers to insects, they must be sealed at the sides and ends of the rows, (i.e., edges covered with soil) so that insects cannot crawl under them.

Traps can attract insects by using color, taste, and sex hormones. For example, yellow sticky traps will lure aphids, whitefly, thrips, and leaf miners. Slugs have a particular liking for stale beer and will drown in a shallow saucer of it placed in the garden. Japanese beetle traps commonly use sex hormones and floral lures to attract the adult insects to them.