Here is a simple, effective method many homeowners use to remove green algae from siding with minimal effort.
Easy Spray-On Method for Removing Green Algae
What You’ll Need
- Household bleach
- Water
- Liquid dish soap
- Garden pump sprayer (or spray bottle for small areas)
- Garden hose
Cleaning Solution
Mix:
- 1 part household bleach
- 3 parts water
- A few drops of liquid dish soap (helps the solution cling to the siding)
Example:
- 1 quart bleach
- 3 quarts water
- 1 teaspoon dish soap
Step-by-Step Instructions
- Protect plants and grass
Lightly spray nearby plants with clean water before applying the solution. This helps dilute any runoff. - Apply the solution
Spray generously onto the affected siding, starting from the bottom and working upward to avoid streaking. - Let it sit
Allow the mixture to sit for 10–15 minutes. Do not let it dry completely. - Rinse thoroughly
Use a regular garden hose (not high pressure) to rinse from top to bottom.
Most algae will disappear without scrubbing.
Important Safety Tips
- Wear gloves and eye protection.
- Never mix bleach with ammonia or other cleaners.
- Avoid pressure washers at high settings — they can force water behind siding.
- Test a small area first, especially on painted or older siding.
Alternative (Plant-Safer Option)
If you prefer to avoid bleach, use oxygen bleach (sodium percarbonate) mixed with warm water. It is gentler on landscaping but still effective.
If you tell me what type of siding you have (vinyl, wood, fiber cement, brick, etc.), I can give you the safest method specific to your home.
