Outdoor stone sculptures add elegance to gardens and landscapes, but algae growth can quickly diminish their beauty. Preventing algae requires a combination of proactive measures and regular maintenance. Here are the most effective methods:

1. Regular Cleaning: Use a soft brush and mild detergent to scrub the surface monthly. Avoid harsh chemicals that may damage the stone.

2. Natural Solutions: Apply a mixture of white vinegar and water (1:1 ratio) to kill algae spores. Baking soda paste can also help remove stubborn growth.

3. Proper Placement: Ensure sculptures are placed in well-ventilated, sunny areas. Algae thrives in damp, shaded spots.

4. Sealants: Apply a stone-specific sealant annually to create a protective barrier against moisture and algae.

5. Copper Strips: Place copper strips near the base of the sculpture. Rainwater reacting with copper releases ions that inhibit algae growth.

For severe infestations, commercial algae removers designed for stone surfaces can be used sparingly. Consistent care will keep your sculptures pristine for years.