You can buy dried and dyed moss at many larger craft stores, but it's more of an adventure to go and collect it yourself, if you are lucky enough to live near a river or forest.
It's best to go the day after a rain. Wet, living moss is a joy to hold and touch, and peels off the rock in a large, cohesive sheet, if you're careful. There are so many textures and varieties right in my own backyard!
Get more than you think you'll need. Using moss growing on rocks works a bit better than moss from a tree or the ground, since there's less bark or dirt to remove.
Soak your moss in water overnight, then lay it out to dry. I sprayed mine with the hose to help get rid of any remaining dirt or leaves or insect forest friends.
Fill a large pot with:
- 1 part glycerine
- 2 parts hot water
- A bit of green fabric dye
- A dash of white vinegar to set the dye
Submerge the moss completely, and leave it in there for an hour or more, until the water cools down. Wring the preserved moss out -- you can wring it into your pan and reheat and reuse the liquid for the next batch. Lay it out and let it dry completely.
Wear gloves to keep the dye off your hands!
More About Dyeing & Coloration
I used a forest green and a deep yellow dye from Dharma.
You could also use RIT dye (usually used for tie-dye) since that's pretty easy to find -- they have it at any craft store, or at most grocery stores in the craft / school supply section.
I wasn't all that scientific about how much dye I used. I wanted a range of greens from light to dark for my finished piece, so I just added more whenever I felt it was needed.
The glycerine solution preserves the softness of the moss, but not the color. As it dries out, it will turn brown if you don't use dye. Here's an image showing fresh moss, preserved moss, and preserved and dried moss.
As you can see, the fresh moss is still much more vibrant and appealing than the dyed moss. I may have had better results using a lighter green dye, but the forest green color was what I had on-hand. It was a little darker than what I wanted, so I had to get a little creative.
The reason bright living moss looks so very vibrant in the spring time is that it's putting out ultraviolet light. Apparently, moss can send out signals in UV/A light, though it doesn't seem to be a very well understood phenomenon yet.
So, to recreate the look of vibrant, living moss, I added some UV pigment in green and yellow. I just painted it over the top of the moss with a wet paintbrush after the moss was mostly dry from the dyeing.
This worked like a dream. My moss is vibrant and glowing and looks almost alive. It's Zombie moss! Also, this step had the added bonus of giving me control of more of a range of colors for my final artwork.
And if I shine blue/purple NeoPixel lights on it, I get a bit of fluorescent play on the moss tips! Yes, it sounds a bit weird, like a velvet Elvis painting, but it sure looks lovely.