Easy, Harmless Ways To Get Rid of Moss

Coping Constructively With Mossy Madness

I always get a kick out of earnest magazine articles that explain how to create a mossy patina on clay pots. Evidently clean terracotta pots looks too obviously new and a mossy coat will give them an authentic, ancient English look. Well, the good news is that we Northwestern gardeners don’t need to mess with buttermilk or buy packets of pulverized moss starter. All we have to do is wait, and not very long. Before you know it, your pots will be mossy, and probably your house will be too.

If not actually mossy, our houses (and pots, and deck furniture) often accumulate a thin coating of pollen and mold, which has that authentic old English look as well. One way to deal with this is to paint buidings and outdoor furniture that same color. Indeed, my house is painted with Benjamin Moore Nantucket Grey, with Sussex Green trim, both of which are a pretty good match for the pollen/mold blend in my region. I discovered this by taking a piece of pollen-crusted wood to the paint store and matching it to paint chips. So simple!

A Kitchen Moss Remover

Of course, paint just hides the problem (and I’m fine with that). I find the very best way to reduce moss and mold presence is with plain old baking soda. Years ago, I used a home-made baking soda spray with a sticking agent that was great for cleaning up mossy furniture, decking, walkways and so on. A few years ago I learned that all you really need to do is sprinkle plain baking soda around. I’ve since tried it and sure enough, it works beautifully and surprisingly fast.

For the past few years, I’ve kept my north-facing roof moss free by sprinkling it with baking soda each summer. Recently I treated a very mossy stone walkway with baking soda and despite the cool, damp weather, the moss was all dead in a week. Here’s how it works: Sprinkle roofs, decks, furniture, and walkways generously with baking soda. Next, even out the coverage with a broom or brush. Let it stand for a few days, or until moss turns golden and starts to flake away. Scrub or scrape off moss and rinse away excess soda and you’re done until next year. This is effective with getting rid of the mold/pollen buildup as well.

Safe and Simple

The best aspect of this totally simple treatment is that, unlike most commercial moss killers, baking soda won’t harm garden plants, soil, or water. Dumping a whole bagful on a given plant won’t be helpful, but runoff from a roof or deck cleaning job won’t hurt anything. In fact, some plants, from tomatoes and blueberries to hydrangeas and geraniums, prefer acidic soil conditions and may even grow better.

I was also asked by a reader  whether he could safely collect rainwater off his roof if he used a toxic moss killer to keep the roof clean. The answer is no. Rainwater contaminated with zinc, iron or copper should not be used on edible plants and why not switch to basic old baking soda?

The Non-Metallic Answer

Moss killers based on zinc or copper create toxic runoff that can harm fish and aquatic life (as well as people, in high enough concentrations). Iron solutions are less toxic (though not entirely harmless) but they can permanently stain roof shingles, decks, siding, and lawn furniture, as well as concrete walkways.

Is it possible to prevent moss from invading lawns and garden beds in the first place? Well, this is the moss capital of the world, but there are some things that will help. Most important are to improve the amount of light and air circulation in the garden and to change soil from fungal to bacterial domination. That last is best accomplished by adding compost annually to beds and lawns to balance soil acidity and open up compacted soils. Have a skilled arborist prune trees to allow more light and air to reach shady areas. Finally, don’t over-plant tall shrubs and trees again!

Foliar Spray For Plants

Almost equally simple is this anti-fungicidal solution, which is effective against powdery mildew and molds on plant foliage. It’s also safe to use on edible plants (just rinse well as usual before eating them), and on lawns with red thread or fairy mushroom rings. in addition, this baking soda solution helps prevent early blight on tomatoes, a common problem in the maritime Northwest.

Baking Soda Solution For Plant Problems

1 tablespoon baking soda (any kind)
2 tablespoons canola oil
1 gallon water
1/4 teaspoons mild castile liquid soap (Dr. Bronner’s or similar)

Thoroughly wet down affected foliage/lawn, then apply this milder version, shaking the spray container frequently to keep solution from separating. Spray foliage top and bottom (if applicable) or saturate well (lawns). Repeat weekly or as needed.

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31 Responses to Easy, Harmless Ways To Get Rid of Moss

  1. Wes says:

    Thank You! We moved to the great NW in Oct. & have been wondering what would be the best way to get rid of this concoction growing on everything :-).

  2. Vanessa says:

    How about a grapefruit tree with moss, would i be able to use the same solution to help get rid of it and heal it back to health?

    • Ann Lovejoy says:

      Hi Vanessa,

      Well, no. Moss on trees is not always a sign of anything but age. Here in the maritime Northwest, even shrubs get mossy and it does them no harm. Given that you are growing grapefruit, I’m guessing you live someplace significantly warmer than my neck of the woods. If the “moss” in question is Spanish moss, it really isn’t moss, but is epiphytic, like orchids, plants that get nourishment from the air, not from the tree. You can remove it, but it will probably come back. It might be a good idea to have an arborist take a look at your tree, because very mossy trees are likely to be that way because of some underlying cause (age, disease, pest damage). Hope that helps!

      Ann

  3. Mitzi says:

    I am curious what you used for the “sticking agent” in your spray method? I typically use a spreader sticker and in the past have just used mild soap. There is a place on my roof that I want to try this method and since the rain has more than had its fun already I don’t think the sprinkle method will work and it is a pretty high pitch to get to but I can spray it with a hose end sprayer. Thanks for all the other info.

    Mitzi

    • Ann Lovejoy says:

      Hi Mitzi,

      Usually I just use an organic dish soap or liquid castile soap (plain Doctor Bronner’s) as a sticking agent. It works really well. Once I had nothing but lavender scented Dr. B’s and it even smelled delicious…

      Ann

  4. Ted Thayer says:

    My old brick patio was covered with moss.

    I applied a solution of baking soda in water liberally with a broom. Let it set a few days and all the green moss turned brown/yellow which washed off with a good hosing.

    However, a black, slippery when wet, thin caking has remained on most (about 50%)of the patio bricks. No amount of hosing or sweeping removes it.

    Any suggestions?

    Thanks, Ted Thayer

    • Ann Lovejoy says:

      Hi Ted,

      I suspect the moss left some of its rootlets behind. Try scrubbing with more baking soda (dry-ish, but use a little water to make a paste), or you can try a mild bleach solution. Hope that helps!

      Ann

  5. Beth Young says:

    Hi Ann,
    I really appreciate your post; you have always been my favorite garden writer. My homeowner’s insurance company (Progressive) just informed me that they are denying me coverage because they found moss on my roof. It’s not much but I guess they did a drive-by and my house faces the north. Anyway, I want to get it off asap and it is now Feb 12. Any suggestions for winter removal?

    • Ann Lovejoy says:

      I’d still use baking soda, which I get in BIG bags from Costco. Even in winter, it can turn moss brown, and it will fall off as it dies. You will probably need to repeat the dose after each big rain (which is pretty often) if you do it at this time of year.

      If you get help (as I do; no roof work for me anymore!), be sure to work with folks who know how to climb around on a roof without damaging the shingles. I did have a crew carefully scrape off the moss by hand once (which cost a lot, and did not last very long), but have found that warm-weather applications of baking soda are less expensive and longer lasting. Sorry we can’t do much about the weather!

      Ann

  6. Martin says:

    Hi,
    I’m just wondering does anyone know how to get rid of moss
    On a lawn in an environmentally friendly way, I have lots of moss on my lawn
    This year and it can be expensive to treat, especially when it comes back year after year.

    • Ann Lovejoy says:

      Hi Martin, try this:

      Foliar Spray For Plants

      This anti-fungicidal solution is effective against powdery mildew and molds on plant foliage. It’s also safe to use on edible plants (just rinse well as usual before eating them), and on lawns with moss, red thread or fairy mushroom rings. in addition, this baking soda solution helps prevent early blight on tomatoes, a common problem in the maritime Northwest.

      Baking Soda Solution For Plant Problems

      1 tablespoon baking soda (any kind)
      2 tablespoons canola oil
      1 gallon water
      1/4 teaspoons mild castile liquid soap (Dr. Bronner’s or similar)

      Thoroughly wet down affected foliage/lawn, then apply this milder version, shaking the spray container frequently to keep solution from separating. Spray foliage top and bottom (if applicable) or saturate well (lawns). Repeat weekly or as needed.

  7. Rhonda says:

    I have increasing amount of moss in a lawn with fruit trees. Granted as the warmer weather comes I see more grass growing through it but wondered if the plant mixture you posted would be okay to use on the moss and the fruit trees? The PNW is known for its greenery…both good and bad! I have used tide powder on the roof and it did work but I think baking soda would be better. Thanks

    • Ann Lovejoy says:

      Hi Rhonda,

      Yes indeed, baking soda would be far better to use on your roof than a detergent. It looks like you and Kim (see above) have similar issues, and the same reply is suitable for you too. Shady areas are not well suited to lawns, and trees of all kinds, fruiting or otherwise, do better without a grassy carpet. Consider replacing turf around the trees with a 3-foot circle of airy mulch, such as bedding straw. Moss on the trees themselves is not an issue; at least, not here in the Northwest, where moss is an important part of the ecosystem. Hope that helps!

  8. Liz says:

    Your article had me chuckling. Thanks for the tips.

  9. kim says:

    I was wondering if the baking soda will hurt my raspberry plants ,as this year there is alot that appeared on the ground at the base of the plants. Also can I put baking soda on the lawn to kill the moss in it too.

    • Ann Lovejoy says:

      Hi Kim,

      Since baking soda has been used for decades as a natural fungicide in many organic sprays for all sorts of woodies, including fruit trees and rose bushes, I don’t see how it could do any harm to raspberries (rose family, after all). However, rather than dumping a lot of baking soda around your raspberry plant I’d do a few other things first. Are they in a lot of shade? It might be best to prepare them a new home in a sunnier spot and move them there in the fall. If not, perhaps the soil is fungally dominated (common where woody plants have grown for a long time. Try removing the moss with a hand rake, then spraying the soil with a bacterially dominated compost tea, and/or adding several inches of mature compost around each plant. The improved aeration and biodiversity should improve the soil and also give the plants’ roots a boost.

      As for the lawn, yes, you can again rake away moss and rake in some baking soda, but again, underlying issues may need addressing. If the lawn area is shady, rake in compost and oversow with a shade tolerant turf seed blend, or consider making a mossy shade garden instead of having a mossy lawn.

  10. Mary says:

    What can I use to get rid of the moss in my yard. Front and back is full of moss and my dogs like to try to eat it. they are always digging it up and chewing on it. I need to know what I can use that will kill the moss and not harm the dogs.

    • Ann Lovejoy says:

      Hi Mary,

      Unfortunately, baking soda is toxic for dogs, so I suggest turning your mossy lawn into a mossy fern garden instead. Moss thrives in shade and in soils that are fungally dominated, places where woody plants (trees and shrubs) grow or have grown in the recent past. When moss persists in full sun, that is often the reason. If your lawn area is sunny, find a source for compost tea and/or spread several inches of compost over the entire area. That will help alter the soil, bringing it closer to bacterial dominance (which grasses and perennials prefer) and also making it less acid and closer to neutral. Hope that helps!

      • Tyler says:

        I have a summer home and am grateful for the moss lawn because I only have to mow once or twice a year. If moss can co-exist then I say let it be.
        Moss on the roof is different though, that can result in ceiling leakage issues.

        • Ann Lovejoy says:

          Insurance adjusters do not like to see moss on roofs, so keeping them clean boosts your home value as well.

  11. Irene Vale says:

    Ann, I have also found that a plastic frosting container with holes punched in the top is a great way to apply baking soda. You just have to squeeze the container to blow a dusting onto the soil. I was so excited to find that baking soda is great for killing the leafy pest (I think they are liverworts) that are often found on the top of the soil of purchased plants. This green growth spreads like wild fire by spores and will cover your beds and grass! I am going to try your solution for easier coverage. Thanks for the tips!!!

  12. Weezer says:

    Being a Seattleite I certainly have a problem with moss. During winter it grows on the North side of my body. So I took your advise. I rubbed baking soda into the moss. Sure enough, after two days it simply washed off in the shower.

  13. Darcy says:

    Hi,
    Thanks for the advice. I have a problem with moss growing on my patio. Can’t wait to try the baking soda on it. I have a question though. I just got a hydrangea. I know they like acidic soil, and you stated that baking soda is good for them. Baking soda is alkaline so why is it good for hydrangeas?
    Thanks,
    Darcy

    • Ann Lovejoy says:

      Hi Darcy, as I explained to the Nelsons, I said it wrong. However, you CAN use baking soda on hydrangea foliage if it gets mildew or mold, AND if you want them to have pink flowers instead of blue ones, you can dump some baking soda around the roots every few weeks from spring into summer.

  14. Norm & Marge Nelson says:

    I thought baking soda was “not” acidic, but you say it is good for acid loving plants such as blueberries. Did I read this wrong?

    • Ann Lovejoy says:

      No, you read it right, I said it wrong. What I should have said is that you can safely spray the baking soda solution on everything from roses to blueberries to clear up many foliage disorders, like molds and mildews. In fact, baking soda is not acidic but alkaline, and is sometimes used for neutralizing acidic soils (as when people want pink hydrangeas instead of blue ones). Good catch!

  15. Patti Chabot says:

    I am writing to you on behalf of the South Surrey Garden Club from just north of you in Canada. We have hired a bus to bring 40 people to the Kitsap Pennisula on August 5 and 6th of this summer to see the gardens of your area. Dan Hinkley is hosting us as well as Heronswood. Ideally we would like to visit one more private garden in the afternoon around 2-3pm. I think you garden in this area and am respectfully asking if you ever show your garden? If so, is there any possibility of visiting on the 6th of August?
    I would also appreciate any information on your area of interest to a group of avid gardeners.

    Patti Chabot 1-604-535-5926
    Past Program Chair
    South Surrey Garden Club.

    • Ann Lovejoy says:

      Hi Patti,

      Well, it sounds like you are going to have a lovely trip. I would suggest that you visit the Bloedel Reserve on Bainbridge Island. If you want to see may gardens, you can tour the Bainbridge Island Public Library grounds, where I’ve been gardening with the Friday Tidy volunteers for over 17 years, as well as the Waypoint, the island’s newest park by the ferry dock, where I recently installed about 5,000 plants, including many interesting natives. Hope that helps!

      Ann

  16. Judy says:

    I just noticed after yesterday’s rain the surface of the soil around the vegetables in my garden is very deep green. Is this the beginning of moss growth? (I did have moss growing there last year, but when I did my soil test it tested alkaline?? Maybe I did it wrong?) Would a baking soda sprinkling remedy this without hurting my vegetables? Should I mix it with water and sprinkle over all, rather than a powder shake? I would love some advice!
    Thanks!

    • Ann Lovejoy says:

      Hi Judy. Hmmm. The soil itself is green, or something growing in the soil is green? I would suggest that you take a picture and show it to your local nursery folks and see ht they say. Another good place to get an idea about what’s going on is your local agricultural extension agent. You can also check with your local county government to find out when and where you might find a Master Gardener clinic. Without a better idea of what you’ve got going, I would not do anything except perhaps use a hand cultivator to stir up the top few inches of soil and add some mature compost. Good luck!

      Ann

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