Lichen growth on outdoor chairs is a common problem that combines fungi and algae in a symbiotic relationship, thriving in damp, shaded environments. The most effective treatment involves a multi-faceted approach combining immediate removal and long-term prevention.

For existing lichen, begin with a thorough cleaning using oxygen bleach solution (1 cup per gallon of water) which is less damaging than chlorine bleach. Apply with a stiff brush, scrubbing in circular motions. For natural alternatives, white vinegar or baking soda paste can be effective for milder cases. Always test cleaning solutions on inconspicuous areas first.

Preventative measures prove most crucial. Apply waterproof sealants or specialized anti-fungal coatings specifically designed for outdoor furniture. These create protective barriers that inhibit spore attachment. For metal chairs, consider powder-coated finishes which provide superior protection compared to paint.

Environmental modifications significantly reduce recurrence. Position chairs in sunny, well-ventilated areas when possible. Implement regular cleaning schedules using mild detergent solutions, particularly after rainy periods. For permanent outdoor installations, consider using lichen-resistant materials like treated wood, aluminum, or synthetic rattan during initial purchases.

Physical barriers including protective covers during extended wet periods provide additional protection. For severe cases, commercial anti-lichen products containing quaternary ammonium compounds offer professional-grade protection, though always follow manufacturer instructions for application and safety.

Consistent maintenance remains the ultimate solution - regular inspection and immediate treatment of early growth prevents established infestations. Combining immediate removal with ongoing preventive strategies ensures chairs remain lichen-free throughout the year.