If your white siding is beginning to look a little green then this is the route you want to go as it is very powerful against mildew and mold.
How to clean vinyl siding without a pressure washer.
Paint dealers also sell mildewcide that can be used.
If mildew is present use a solution of 1 quart of bleach to gallon of water and a small amount of the tsp detergent.
You can go hunt down a power washer or you can get in touch with your inner alchemist.
If you just moved or have lost your power washer you may want to clean your siding without a power washer.
Cleaning your siding helps your home look great and can extend the life of your siding.
Cleaning your siding by hand or with an outdoor cleaning wand has the added benefit of greater precision and is better for many types of siding.