Green mossy mess

You're going to wash it off by hand? Whew, that's a lot of work! Use warm soapy (Dawn) water with a little bleach and a scrub brush. Then hose it off.

Spray bottle of mold and mildew cleaner can be bought at hardware stores. Spray, let set for recommended time and hose off.

I Seriously don’t recommend doing it by hand! Been there, done That! Ugh! You can easily rent, use and return it in one day! You can use a mix of bleach & dawn dish soap! You are otherwise you (and your arms, back and Entire Body will Thank You!

You can buy moss killer at Lowes or Home Depot, or use bleach/water mixture in a spray bottle.

There are specialty products make to remove moss and mold on siding.... and you can RENT a pressure washer... most home improvement stores rent stuff like this.

for the correct response....Wet and Forget

Use a broom (and a handle extension, if needed) and a pail of water with a little Dawn and 2 cups of bleach. Scrub away with the broom, and then hose down.

For moss on my roof, I used Wet and Forget from a sprayer. Exactly as described, you don't have to do anything else. It works over time, and doesn't damage nearby plants.

I've used Simple Green with great results. Dilute it, spray it on, let it sit for awhile and then hose it off. May depend on how mossy it is though. If real mossy may need to use a brush.