Myth-busting: Moss & Acidic Soil

By the Renegade Gardener, a/k/a Don Engebretson

“Moss growing in lawn is a sign of acidic soil”

Here we have one of the most dangerous kinds of myths possible: one that is only vaguely correct.

Yes, low pH, i.e. acidic soil, can contribute to moss growth in the lawn. But low pH alone is almost never the cause for moss growth. But that doesn’t stop gardeners with a moss-in-their-beloved-grass problem from resolutely scattering lime dust all over the area spring, summer and fall-only to discover that moss will grow quite handsomely in “sweetened” (high pH) soil. Go take a hike along the Mississippi River some summer. What’s that growing on the limestone bluffs? Moss.

To grow moss in your lawn, all that is required is insufficient sunlight, low soil fertility, compacted soil, dampness, low pH, usually in a combination of two or more of the above. Achieve all those conditions in a single patch of yard and I say to hell with growing grass, set up a Zen garden. You’ll have moss covering a new statue of Buddha in about twenty minutes.

Lack of direct sunlight is the number one contributor to moss in the lawn. It’s always shady where you find it. Again, I don’t care if your soil pH is 5.0, if the area is getting a full day of sun, moss won’t grow.

The area is usually wet. Well, that makes sense; shady areas stay moist longer. Low soil fertility is another condition that welcomes moss. Low soil fertility in lawns is the norm for 99% of the lawns in America; that’s why the Scotts Company is on your radio right now advertising that now is the time to apply the first of your FOUR recommended lawn fertilizer applications for this season. Compacted soil is another great moss incubator. Compacted soil makes it tough for grass to take hold and flourish. The lawn stays thin, allowing ample room for moss.

Don’t be out there spraying “Moss Buster” all over your poor, hard, dark, damp, infertile lawn. It doesn’t work. Nor does raking it all out. It’ll just grow back thicker. Moss is only the result of the problem — fix the problem.