Moss--How do I get rid of it?

[NiceGuy]

I suppose this is the right group to ask about plants; if not please direct me elsewhere.

I have green moss growing on my sidewalk, front wall, steps, and the house wall behind some plants.

A 50% dilution of regular household bleach kills the stuff on the sidewalk, steps, and front wall. Spray it on, wait half an hour, hose it off. The part that doesn't disappear (in the cracks) turns a shade of yellow which I presume means that it's dead and some sweeping and scratching will remove it.

I'm loathe to use such a powerful mixture on the house wall because the run-off will go all over the plants and even if I cover them it'll end up in the soil possibly killing them (I think). I've tried (gingerly) a 10% solution but that didn't do anything. The wall is porous limestone and is painted so it doesn't matter if the mode of killing causes a stain. I'll repaint it anyway. Does moss require oxygen to live? If so would painting it with shellac do the trick? Is there some other appropriate chemical that will kill the moss but not the plants? BTW the plants are a yew tree and an azalea if that makes a difference.

TIA

[Betsy]

I just de-mossed my fence with a power washer. It worked great, took little time and effort, didn't hurt the fence, and best of all didn't hurt the plants. I used nothing other than the force of the water.

[Philip Lewis]

Moss likes an acidic enviroment. Increasing the PH might be the way to go. I might suggest:

get rid of any black spot on your roses too. ;)

Azaleas are acid lovers as well.. so a basic solution might be detrimental to their health. Perhaps treating the soil in the immediate vicinity with an acidifier (magnesium sulfate?) will help to counteract the mixture.... of course, then you are playing with making salts which may or may not be detrimental.

whee... isn't chemistry fun!?

[theoneflasehaddock]

The post about a power washer probably had the best idea.

Oddly enough, fertilizer will kill some types of moss. But not neccesarily all types, and the kind you have sounds pretty invasive.

drying it out might also kill it, if you've been watering the area alot.

-

theoneflasehaddock

[Phisherman]

There are anti-moss sprays you can try. Moss is a plant and requires CO2, light and moisture to survive. But, moss prefers shady, moist, and acidic conditions. I have heavily limed an area and this had the effect of less moss growing. Are you sure it is moss and not algae?

[NiceGuy]

Any names to suggest?

So shellac should seal out the CO2 and kill it????????

Except at around 4pm there's almost no direct sunlight in the area but I would have thought that limestone (on which it's growing) was alkaline. Maybe the paint (latex and peeling) is acidic?

I've been in this house for over 25 years and this "moss" just appeared out of nowhere last year. I'm not sure exactly where it started but it covers the sidewalk (more near the front walls) and the front courtyards of my neighbors for about three houses on either side of me. It even grows on the steel (black painted) coal hole cover in the front of the house. The only thing I can recall that's different is that prior to last year I used to hose down the front and the sidewalk about three times a week. Due to other commitments, I've had to stop doing that except for maybe once a month. In any case that wouldn't explain the neighbors.

I thought algae was a fancy name for seaweed. It certainly doesn't look like any seaweed I know. It's bright green and resembles velvet such as you'd use to line a jewelry box. Except on the steel and the smooth portions of the concrete it seems to be slightly spongy.

Thanks to the other posters but I can't really use a power washer on the difficult part (the front of the house) because of the porous limestone. I have a small electric power washer that I use to wash the car (occasionally ) and the last time I painted the steps (also limestone) I thought I'd be smart and wash away any peeling paint. Bad idea! Even on low pressure the power washer gouges holes in the limestone and blasts the mortar out of the joints. I could use it on the sidewalk and the other concrete areas but the bleach solution works just fine there and the residue won't run into the plants.

[Travis]

Moss does very well in a shady, moist, cool environment. Once you get rid of the moss let in the light and keep the area dry.

Apply the 50% solution carefully, with a paint brush or roller that should keep most of it off the soil.

[Pat Kiewicz]

There are moss killers and preventatives on the market.

One is sold under the Safer brand:

's another available here: 've bought other products from bugspray.com and found them courteous and reliable.)

And these people go into detail about their product (click through to other pages, including an FAQ):

The products claim to be safe for use around other plants. The FAQ for the last cited says:

1. Will Anti-Growth harm plants or shrubs?

A. Anti-Growth will not kill plants or shrubs but can brown the foliage. Plants should be protected with a ground cloth or sprayed with water to dilute before and after the Anti-Growth application.

[SVTKate]

"Philip Lewis" concocted:

| >BTW the plants are a yew tree and an azalea if that makes | Azaleas are acid lovers as well.. so a basic solution might be | detrimental to their health. Perhaps treating the soil in the | immediate vicinity with an acidifier (magnesium sulfate?) will help to | counteract the mixture.... of course, then you are playing with making | salts which may or may not be detrimental. | | whee... isn't chemistry fun!? | |

Ouch! My head hurts now! ;¬D Kate

[TOM KAN PA]

Are you sure you want to get rid of it? People are paying big bucks for moss gardens!