Will algae grow on vinyl siding as well as on aluminum?
Mold's much worse with vinyl, as far as I've seen...dirt and mold on Aluminum are comparatively non-existent. That plastic crap is garbage! I went to my first ever vinyl siding 7-years ago and in 5-years it was butt-ugly with dirt and especially mold, even with annual water wasting hose-off's.
I don't have heavy plantings or trees on the house and get Sun on all sides. But with vinyl, it grabbed everything. And no, rains don't wash it (amazingly). Horrible stuff that I'll never get nor keep again. I just spent Painting-Efforts to clean my joining-the-crowd mistake. Vinyl's THE worst!