Grubs can wreak havoc on your outdoor plant boxes, damaging roots and stunting plant growth. Fortunately, you can create an effective grub deterrent system using natural and cost-effective methods. Here’s how:

1. Use Beneficial Nematodes: These microscopic organisms target grubs without harming plants. Simply mix them with water and apply to the soil.

2. Apply Diatomaceous Earth: Sprinkle food-grade diatomaceous earth around your plant boxes. It dehydrates grubs and other pests upon contact.

3. Plant Grub-Repelling Plants: Marigolds, garlic, and chrysanthemums naturally repel grubs. Interplant them with your vegetables or flowers.

4. Introduce Milky Spore: This natural bacteria infects and kills grubs over time. Apply it to the soil for long-term protection.

5. Maintain Healthy Soil: Aerate your soil regularly and avoid overwatering, as grubs thrive in damp conditions.

By combining these methods, you can create a robust grub deterrent system to keep your outdoor plant boxes healthy and thriving.