I know that some folks use a buttermilk slurry to establish moss, but I've never heard of anyone feeding moss directly.

I'm sure Terrestrial Man can give you some pointers.

Josh

I do not recommend any moss for a southern exposure site and one that is permanently wet. The only moss that would handle such a location would be sphagnum and it requires cool temperatures to do well so the southern exposure could be hard for it to establish itself well.
Your best bet are marginal aquatic plants. These are plants that grow in the wet ground by bodies of water or in marshes, such as cattails. There are several nice oranmanetal types, such as Pickerel Weed that are available that could do well in your site. Check out the link below.

Here is a link that might be useful: Index of Aquatic & Marginal Plants

im sorry i lied its north facing :) little off, dont know what diffrence it makes

Post a picture of the flower bed. I will try and give ideas that could help. I have grown moss in all compass directions. Think Kyoto Moss Gardens! That garden grows moss everywhere. Although Moss likes cool temperatures (cooler than most plants) The fact is the stuff will even grow in full sun. The conditions need to be livable. Yes, you can feed moss. My favorite item in decomposed leaf mold and decomposed and ground up pine bark. Peat moss that you buy by the bail is great for a soil conditioner. What a better food additive than the components of moss! Some people make Sphagnum tea to water with. My first Bonsai garden had an southern exposure. The moss I grew was for sale. The trick was the Mister system I put in and the fact the area did not get sun all day. It will be hard to believe but the area received full sun from 10am to 2pm. The area grew moss like a weed. If the sun does not stay on this plant too long, "Brunnera, Siberian Bugloss", it is a great item for a shaded area. Stick with the solid green leaves. If the plant isn't in moist soil and the sun hits the leaves it will "burn" like a vampire! If this will grow the light for moss is great. The best way to grow moss is collect all the information from all sources. Then look at your conditions and adjust them if needed. I added a mister system. I also put up a small shade cloth to cool the air. It did not shade the plants but kept the hot sun from bouncing off my house and heating up the area. I know this is long winded but I couldn't get moss to grow worth anything and now my biggest obstacle is the squirrels! They love my moss to make their nest with.