Cutworms can wreak havoc on your outdoor plant boxes, destroying young seedlings overnight. Fortunately, you can create an effective deterrent system using natural and DIY methods. Here’s how:

1. Use Collars Around Plants: Cut strips of cardboard or plastic and place them around the base of each plant, burying them about an inch into the soil. This creates a physical barrier that prevents cutworms from reaching the stems.

2. Diatomaceous Earth: Sprinkle food-grade diatomaceous earth around your plants. This natural powder dehydrates and kills soft-bodied pests like cutworms without harming your plants.

3. Beneficial Nematodes: Introduce beneficial nematodes to your soil. These microscopic organisms prey on cutworm larvae, reducing their population naturally.

4. Coffee Grounds or Eggshells: Scatter used coffee grounds or crushed eggshells around your plants. The rough texture deters cutworms, and the coffee grounds also enrich the soil.

5. Nighttime Patrol: Handpick cutworms at night when they’re most active. Drop them into soapy water to eliminate them.

6. Companion Planting: Grow plants like garlic, onions, or tansy near your vulnerable crops. Their strong scents repel cutworms and other pests.

By combining these methods, you can create a robust cutworm deterrent system for your outdoor plant boxes, ensuring a healthy and thriving garden.