Control Moss With Laundry Detergent

I live in the Pacific Northwest where every year the skies are filled with clouds 226 days and rain 155 days. These are ideal conditions for growing moss. If left unchecked moss would cover my roof, driveway and sidewalks. I even have some moss growing on my car!

Supplies

Any powdered laundry detergent should kill moss. I use Costco Laundry Detergent, it's the same powder I use to wash our clothes. I have used home improvement center moss-control products, but found them to be expensive, toxic and don't seem to work as well.

Step 1: Test Area

I mostly use the detergent treatment to control moss on the roof of my house. It's more than an appearance issue, moss shortens the life of shingles and causes leaves and needles to accumulate which contributes to leaky roofs. To illustrate how well detergent works, I treated a section of concrete wall next to my driveway.

Step 2: Detergent on One Side

For this demonstration, the left side of the wall was untreated and the right side had a light sprinkling of detergent. Only a little detergent is needed. On my roof, I only sprinkle detergent on the ridge lines and let the rain deliver it to the moss growing on the edges of the shingles. Sometimes I treat persistently mossy areas with a direct application like the roof corners or along a gable.

Step 3: Results

Here are the results after just seven days and a couple of light rainshowers. From my reading, moss requires a pH of 6-7 and laundry soap has a pH of 9.

Step 4: Car Moss

Did you think I was kidding about the moss on my car?

Comments

[Jack Rodgers]

I lived in South Florida for decades and moved to Tallahassee and rented an inexpensive duplex next to a wooded area (city boy moves to wilderness!). The porch had 3 wooden steps with a nice green color from algae. It became vary slippery during rain time.
I scrubbed it using a household cleaner with bleach and my broom. Then washed it down with more bleach. Gone. Wood shows up not the green slime. Has stayed clean for quite a few months. Next project is to wash down the aluminum siding and windows.

[sawdustagain]

Algae is slippery, glad you found a way to co-exist with Nature!

[Odd Jobs]

Instead of reapplying the detergent once the moss is removed I just use roofing screws and a dollars worth of copper pennies. They are like slow-release fungicide.

[sawdustagain]

That's an interesting idea. I wish manufacturers added some copper or zinc to shingles so they weren't moss candy.

[Odd Jobs]

There are countertops and tiles like that. If you visit a locksmith you can get brass filings that can be dusted down on top of fresh tar... probably using a stencil... hmm.

[MylesS13]

I live in the NW too but have read that detergent is detrimental to asphalt. You are using something on an oil based product (asphalt shingles) that is intended to break down and clean oil out of fabrics. Also I’ve never really had good luck with the commercial moss removal products either.

[sawdustagain]

Yes, I have heard the same. As with most things, if used in sparingly, laundry detergent is relatively harmless to the asphalt shingles. Applied once a year, where needed, the detergent kills the moss and is then rinsed away by rain. Removing moss from roofs is more than a matter of aesthetics, moss deteriorates shingles too and shortens the lifespan of a roof. Alternative treatments like power washing deteriorate shingles much faster. Commercial moss removal chemicals have MSDS sheets that describe their toxicity to humans and aquatic life. For me, that makes common laundry detergent a resonable compromise.

[bpotter107]

I live in ohio, and usually I’d say it doesn’t apply but for those of us living near tall pine trees exceptions are made. I don’t have it on my car yet but my roof nooks and crannies are always GREEN! Thank you, thank you for sharing. Also a tip concerning moss( my moss anyway) BEHR exterior paint does a good job keeping it at bay. Painted my aging white siding on three walls because they were light green lol. Three years later I’m still white!

[sawdustagain]

You are right about BEHR paint. I never thougth about it until you mentioned it, I don't have any moss growing on my BEHR painted siding.