Last year I tried a product to remove the green growing on the north-side siding of my house. I uncovered a product called Wet and Forget.
As it happens, it is a product of low toxicity to us humans and ideal for extremely large surfaces, like houses.
I prefer to remove mold from within my home with essential oils & baking soda, but this seemed impractical for the outside of the home. I suppose weeks of scrubbing is the best alternative, pressure washing works quickly, but damages the siding.
The chemical solution using Wet and Forget works best for me and it’s non-hazardous according to its Material Safety Data Sheet (MSDS.) The amount of active ingredients totals 0.21% and the rest is water. The product is mixed 1 part product with 4 parts water before use. That reduces the effective concentration to 0.052% — and it’s rated as non-harmful.
My research revealed that most vinyl siding contains organic components as fillers. This is especially true in “contractor grade” sidings).
The organic components feed the algae, mold, etc. After 2 applications of Wet and Forget, my siding has been clean of green and black growth with NO PRESSURE WASHING NEEDED.