I received my Oregon green moss from http://www.kinsmangardens.com/ and it is always a process to get it ready to put on the baskets, hayracks and urns. One note, it has never happened in my garden, the leftover moss I had from last year, I donated to my daughter-in-law's urns and the birds are taking it to build nests! I am going to take a chance putting it around my urns and hayracks. Mine is fresh moss, so maybe they will leave it alone.
It comes in a bale all tied with string which needs to be cut away. The moss can then be peeled away in sections (do not soak what you are not going to use) and soaked in water for about thirty minutes. It needs to be squeezed as much as possible and then can be torn, pieced, stuck inside of the rungs of the baskets, and layered between the plants if you wish. This is not like the moss you will buy at Home Depot or the local garden center. It is so natural, green and brown, almost seems like you plucked it from the woods.
Once used outdoors, it lasts for the season. If you have kept it dry from last season, it is still good to go, maybe a little darker. I am going around today to collect the old moss from last year, and I will place it in the middle of my posts between the plantings to conserve moisture. This may seem like overkill and fussiness, but it really does conserve moisture in those pots that are exposed to the heat and sun.
Go ahead, begin "mossing around."
P.S. I bought a large basket of pansys (10 pansies in the pot), and will separate them into two hayracks.
Remember, if you buy those small ones in the flats they will barely get big enough when you will have to take them out because of the heat (if you live in zone 5 or above). I put mine on the north side of my house when they are big and beautiful (around May 1, here in Chicago area).