by OCMGA Master Gardener Vicki Schilleman
We have a cottage in northern Wisconsin where the soil is extremely sandy, conditions are wet (at least most years), and there’s no direct sunlight. My husband spent hours and hours building new steps from bricks and sand, down from the driveway, and I was constantly battling the growth of grass or weeds settling into the cracks between the bricks. Finally, after several years of coddling the growth of moss, I now have a lovely set of steps with moss growing between the bricks — although there’s a way to go yet until it’s where I want it.
There are lots of places where we can’t get things to grow because of shade or moist conditions. Rock gardens always look good with moss between the stones and, of course, a natural, woodland look always needs large rocks with moss. You can grow your own!
The most important ingredient in any recipe for moss is patience (as I learned): it can take years to achieve that fuzzy carpet. The next item on the list is the powers of observation. There are hundreds of different mosses, each suited to a particular ecological niche, and the best way to choose one that will grow well where you want it is to notice what’s already growing there or in a similar location. [Note: I’m chagrined to remember pulling out tufts of moss from between my bricks after they were newly laid because I thought it was ‘spoiling’ the look! Grrr!)
With any luck, the moss you want will be somewhere on your property or that of a friend, because the next step is to collect some. Taking mosses from public lands is not legal; taking them from private ones without permission is stealing. If necessary, moss starts can be purchased; specialists in bonsai supplies sell them.
Collect moss after a soaking rain, or, if that’s not possible, water the mossy area thoroughly. Though there are some mosses that will grow on several different substrates, you’ll have the best luck if you collect from a surface similar to the one you want to cover (wood, soil, or rock).
Take small, roughly 1 1/2-inch diameter patches, and never more than two or three from a square foot of moss. If it is growing on soil, make sure you take the patches with soil attached. Keep the patches moist.
Growing Moss from Slurry
This method is mostly used for hard surfaces such as rocks, flowerpots, and concrete. The idea is to coat the object with a mush of ground moss that contains lots of spores. To get it, you simply process clean moss in a blender, combining it with a thick liquid that will hold it in suspension and help it adhere.
Yogurt and buttermilk are think and sticky — and acidic, which moss likes — and are therefore often used in slurry recipes, but they are not essential. Potter’s clay (from the craft store), thinned to thick-milkshake texture with water, works even better because it holds moisture longer. Diluted manure can also be used if you have a blender dedicated to garden purposes.
For about 3 cups of slurry, enough to coat roughly 1 1/2 to 2 square feet of surface, you’ll need:
- 1 loosely packed cup of moss pieces, or a bit more
- 2 1/2 cups of liquid: diluted potter’s clay, diluted manure, yogurt, buttermilk, or whatever mixture you want to try
- Grind the moss in a blender with 2 cups of the liquid. The result should be about the texture of thin pudding. Add more moss (or more liquid), if necessary.
- Thoroughly wet the object, paint it with the remaining 1/2 cup of thick liquid, then paint on the moss slurry
- Keep the surface constantly moist, using a gentle mist so you don’t dislodge anything. Once a day will probably be enough if the item is in a damp, shady place, but don’t let it dry out. Within six weeks or so you should see the thin green, algae-like filaments that signal new moss is growing.
This method is most often used where the moss will grow on soil, though transplanting will work on any surface as long as it is porous. Before you go out collecting, prepare the site. Remove vegetation (except existing moss, of course). Text for pH and lower it if necessary; most woodland mosses are acid lovers, happiest when pH is about 5.5. Rake the area smooth and water thoroughly.
Collect the moss patches. Place them on the prepared site, pressing down well, then pin them to the soil here and there with twigs to help them bond with their new home. If you’re doing only a small area, you can cover it with the moss “sod”, but otherwise, spread the patches out about 8 to 10 inches from center to center. They will grow together, eventually, as long as you keep the soil between them damp and free of weeds. For faster coverage, make some slurry and spread it between the patches.
Water well right after planting and frequently thereafter. The moss should take hold in about a month. Once it’s established it will tolerate a dry day or two, but not until then.