The idea of using plants for cosmic ray shielding might sound unconventional, but it's worth exploring whether an outdoor plant box could offer some level of natural protection. While plants can't completely block cosmic radiation, they may provide partial shielding through their biomass and water content.

Dense vegetation, especially plants with high water content like succulents or thick-leaved varieties, can potentially absorb some secondary radiation. An outdoor plant box filled with such plants might create a minor shielding effect when placed strategically around living spaces. However, the protection would be minimal compared to traditional shielding materials.

For better results, consider combining plant boxes with other natural shielding methods like earth berms or water features. While not a complete solution, incorporating plant-based shielding into your outdoor space could contribute to a more radiation-aware environment in an aesthetically pleasing way.

Remember that effective cosmic ray shielding typically requires significant mass, so plants should be viewed as a supplemental approach rather than a primary solution for radiation protection.