Cabbage worms can wreak havoc on your outdoor plant boxes, but with a few simple steps, you can create an effective deterrent system to protect your plants. Here’s how:

1. Use Floating Row Covers: Lightweight fabric covers act as a physical barrier, preventing adult cabbage moths from laying eggs on your plants. Secure the edges to keep pests out.

2. Plant Companion Plants: Herbs like thyme, rosemary, and mint repel cabbage worms naturally. Interplant these with your vegetables to deter pests.

3. Apply Natural Sprays: A mixture of water, garlic, and neem oil can be sprayed on leaves to repel worms. Reapply after rain for continued protection.

4. Introduce Beneficial Insects: Ladybugs and parasitic wasps prey on cabbage worms. Encourage these predators by planting flowers like marigolds nearby.

5. Handpick Worms: Regularly inspect your plants and remove any visible worms by hand. Drop them into soapy water to eliminate them.

By combining these methods, you can create a robust cabbage worm deterrent system for your outdoor plant boxes, ensuring healthy, pest-free growth. Happy gardening!