What are the best ways to prevent crevice corrosion in cast iron outdoor flower boxes?

Crevice corrosion in cast iron outdoor flower boxes can be a frustrating issue, but with proper care, it can be effectively prevented. Here are the best methods to protect your planters:

1. Regular Cleaning and Drying – Remove dirt, debris, and moisture buildup, as trapped water accelerates corrosion. Dry thoroughly after rain or watering.

2. Protective Coatings – Apply rust-resistant paint, epoxy sealants, or specialized metal protectants to create a barrier against moisture and oxygen.

3. Proper Drainage – Ensure drainage holes are clear to prevent water accumulation, a key factor in crevice corrosion.

4. Galvanic Protection – Use sacrificial anodes (like zinc) to divert corrosion away from the cast iron.

5. Avoid Salt Exposure – De-icing salts and coastal air can speed up rusting—rinse planters if exposed.

By following these steps, your cast iron flower boxes will stay durable and visually appealing for years. Regular maintenance is key to preventing crevice corrosion and extending their lifespan.