Wendy...do you know what kind of wood your deck is? Or what finish was previously used?
I have been using a line of products from Penofin for over 15 years...they have a great selection of oil finishes as well as a line of cleaning and stripping products.
Power washing should be avoided on most wood decks as it can raise the grain if not done "just right" as far better approach is the bucket and scrubbing broom method...this and the simple garden hose for rinsing.
You can read about Penofins cleaning products in this link.
Bucket with bleach, detergent and water combination. Scurb the algae to hades and back, being sure to kill it all. From there, I can't advise. other tha see if a neighbor is willing to split the cost of renting a powerwasher with you, then use a product such as Restore or what one of the people such as KMS recommends.
Bleach can be tough on wood as it really messes with the Wood's pH...
Wendy, if yu can afford it, you can rent a pressure washer, then let the wood dry realy dry and treat it with a sealer. You would be amazed that it will look like a new deck.
@Wendy, i lucked out and my neighbor a powererwasher this year. I have been scrubbing the deck, as advised above, and that alone, made it look much better. Later tonight, i am going to check out "Restore' for decks. I am also supposed to be getting a sample from Pinofin to try. Will let you know what happens, and which I went with.
Power wash. I just noticed at Home Depot they have a type of paint that has different textures in it to put over old decking. Looked pretty good.
Both HD & Lowes sell a deck finish "Restore". It fills in cracks up to 1/4" deep and leaves a finish that is similar to a ceramic house paint finish. It is suppose to last several seasons with basic cleaning before the need to redcoats. I'm getting ready to finish my deck with Restore.
@LandlightS - can't wait to see the deck Restore(d).
Hey People, Where's the GREEN in you? Just sprinkle (BAKING SODA) all over it, Let it sit 1/2 hour or so & take your (broom or scrub brush) & go to it . Before the baking soda, make sure it's good & wet. I call it the NEW EXERCISE PROGRAM. Please leave the poison out, NO CHEMICALS PLEASE.
Cathie...the "brightener" is use from Penofin is percarbonate and soda lime based...it reacts with water to make hydrogen peroxide...its is pretty safe on you and plants and things. Plus the pH balance is good.
Thank you for all these great ideas...I believe what I'm going to do is try to is power wash, a nice friend is going to let me use his. I also like DeMarie's idea...I have no idea what kind of wood, I just know the wood is old has a horrible color of paint on it that was not made for decks...will let you all know how this turns out...can't make it look worse than it already does:) Again..thank you for so much info. Wen
I have had great success with vinegar killing the moss that grows on our deck.