Q. Mike: I recall you once did a pro-moss piece. I want a solid and secure full-moss lawn; green growth that I won't have to mow. I have deep shade from mature Pines and maples and some moss already growing successfully in my sandy-ish soil. But I need some help; there's lots of conflicting moss advice on-line, especially about "fertilizer". Thanks.
- ---Reverend Jim in Traverse City, MI
- ---Harish in Voorhees, NJ
- ---Linda in Trenton, NJ
Harish is probably also scalping his turf. And he burned up the last of his short-cut shade-loving grass when he cut down those trees and allowed more sun into the picture.
"When moss overtakes a lawn, people think the moss killed the grass, but the truth is that the moss was probably there all the time, growing in the shade underneath the grass," explains William Cullina, ("Kull-EYE-Na") director of horticultural research for the New England Wild Flower Society and author of the new book, "Native Ferns, Moss and Grasses" (Houghton-Mifflin).
"The lawn owner does something that kills or stresses the grass, and the moss becomes more visible. In general," he explains, "proper lawn care— cutting at the correct height, regular fertilization, having a nice, loose well-prepared soil at planting time and keeping the pH close to neutral—all discourage moss.
"That's why people like the Reverend who want to cultivate a moss lawn should do the opposite of good turf care: Keep the soil highly acidic (below a pH of 5 is ideal for most mosses) and don't fertilize", says Cullina. "Any added fertilizer would work against you, as it stresses the moss, but encourages the growth of grass and weeds."
You might also want to un-prepare the soil, he adds. "Many mosses will thrive on the kind of sandy soil your listeners describe, as long as there's regular moisture for the moss. But people who are installing a moss lawn will often deliberately compact the soil first by tamping it down. This creates a nice, flat surface for the moss to adhere to—similar to the rock and stone many mosses grow on in nature—while making it difficult for weeds and grasses to gain a foothold."
If necessary, the good Reverend can purchase some additional moss to fill in his soon-to-be no-mow lawn from a supplier like Moss Acres, a Pennsylvania based company that sells strips and plugs of four different types of moss. Or he can simply cultivate some of his own. You'll find lots of recipes for 'breeding' moss in a blender on the Internet, and Cullina offers this one in his book: Chop up about two cups worth of a moss that's already doing well on your property and place it in a blender with two cups of water and half a cup of beer or buttermilk. Then "don't try and make a green smoothie out of it," warns Cullina, "or you'll kill the moss; just a couple of quick pulses to mix it all up. Then spread it around the area you want to cultivate. Do this on a cloudy or drizzly day and then keep the area well watered—misting would be ideal—until it establishes."
Check the pH of the soil regularly to insure it stays low. Some soils will need a yearly or twice-yearly dusting with sulfur to keep the pH down, but if you already have moss thriving, odds are the pH is just right. Pull any weeds that appear and remove fall leaves and other debris promptly. Cullina notes that moss lover David Benner (whose son runs Moss Acres) lays plastic netted deer fencing over his moss in the fall to capture the leaves. A leaf blower set on reverse would be even better; it'll keep your moss lawn clean and you can empty the collected shredded material right onto your compost pile.
Cullina explains that, like a cool-season lawn, moss may lose its green color during times of drought, but will remain alive; and it will green up amazingly fast when moisture returns. He adds that most mosses can even take some light foot traffic; just don't expect to play Frisbee on it with a hyper-active pooch.
So if you keep trying to grow grass and moss keeps moving in, you have two choices:
- Add lime or wood ash to raise the pH, feed your lawn correctly (for cool season grasses, that's once in the Spring and once in the Fall) and cut the grass high. Or
- Scalp the grass until its gone, keep the pH low, sell the mower and tell people how much you enjoy your no-work sea of green.