If you’re like me and you live somewhere where moss grows abundantly, you probably found some moss growing on your property at some point. Naturally, that raises the question: do you need to do something about it?
Because of its high water retention, moss is usually better off removed before it can cause long term damage to your property or create unsafe conditions.
To better understand why that is, let me break down the details of exactly what kind of damage we’re talking about and how the location your moss is growing can change the answer.
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Should You Remove Your Moss?
The first piece of the puzzle to help you decide if you need to remove your moss is where your moss is growing.
Depending on where it’s growing, moss can cause damage to your property if left untreated or it can be completely harmless.
Here’s a quick summary of when you should remove moss:
| Where Moss Is Growing | Do You Need To Remove It? | Why? |
| On the roof | Yes | Can cause water damage to your roof if left untreated |
| In the gutter | Yes | Can clog/damage the gutter |
| On the tarmac, walkway, or driveway | Preferably yes | Can create slippery conditions and cause damage to your walkway by trapping moisture |
| On your lawn | No | Harmless, but can be a sign of poor lawn conditions |
| On your trees | Optional | Can smother new buds, cover signs of disease, and potentially throw off balance of the tree |
| On your walls | Optional | Can smother new buds, cover signs of disease, and potentially throw off the balance of the tree |
| On your wooden fence | Optional | Moss moisture retention can accelerate rotting and encourage mold growth, but fences should usually be resistant |
| On the car you’ve left outside for too long | Preferably yes | Moss growth can degrade moisture seals |
Unfortunately in most cases, moss should be removed. There are a couple of exceptions, but in general, moss can cause problems down the line if left untreated.
The key problem with moss is its high moisture retention. It attracts water wherever it grows, bringing with it water-related problems like rotting wood and mold growth.
When moss grows in cracks and crevices, the moisture it carries can freeze during the wintertime, causing damage to any seals around your home.
Let me dig into some examples for you.
Moss On Your Roof
Moss growing on your roof is probably the most problematic of places it could grow outside your home.
Your roof is a vital structure that protects your home from the elements, especially rain. When moss grows on your roof and is left untreated, it can significantly shorten the lifespan of your roof.
Moss growing on your roof typically wedges itself under and between your shingles or tiles, where your roof is most vulnerable. As moss grows, it can cause these tiles to lift, creating openings for water to leak through the roof.
Once the water starts to penetrate the roof, there’s an increased risk of mold growth and accelerated decay of the roofing structure. The longer it gets left unchecked, the more extensive the repairs on your roof will be once bigger problems start to surface.
And as you can probably guess, roof work can get expensive.
So if you have moss growing on your roof, it’s best to have it removed sooner rather than later and take action to prevent future moss growth.
Moss In Your Gutter
Moss growing in your gutter poses another set of problems.
At the very least, it’s going to block the flow of water. Moss can catch onto stray debris like sticks or leaves, which will worsen the blockage. Water buildup will add extra weight that will put extra strain on your gutter, which can shorten its lifespan.
When water is blocked, it becomes forced to find another path around the blockage. Blocked water can flow into your basement, into your foundation, or into your home. If that water freezes, it can cause cracks to expand and create slip hazards if dripping onto walkways.
It also creates conditions that attract pests, algae, and mold. You definitely don’t want to find mosquitos or wasps making your clogged gutter their new home.
So definitely make sure to scrape out any moss in your gutter the next time you get around to cleaning it.
Moss On Your Walkway
Moss growing on your walkway might seem like it’s giving it a charming, rustic vibe, but does that mean it’s ok to let it grow there?
The main issue you’ll have with allowing moss to grow on your walkways is that it can create slippery conditions. Where there’s moss, there’s moisture. Where there’s moisture, there should be a yellow sign with a picture of a stick man slipping.
Depending on your surface materials, it can also cause damage by holding in moisture as opposed to letting it drain off your walkway.
It’s also possible that it can leave green or brown stains on your walkway after they get stepped on, which may or may not be a big deal for you.
If you see moss on your walkway, you’re probably better off removing it.
Moss On Your Lawn
Moss growing on your lawn is probably the one place where it’s completely harmless. It won’t do any harm to your grass or plants.
Lucky you.
Unlike weeds, moss doesn’t have any roots, just rhizoids which only attach it to its substrate. It primarily gets its water and nutrients through its tiny leaves above ground. So it doesn’t compete with grass for resources like a weed would.
But that doesn’t mean you’re out of the waters just yet.
When you see moss growing on your lawn, it can be a symptom of unfavorable growing conditions, such as:
- Acidic soil
- Low sunlight
- Too much or too little water
- Soil compaction
So if you were hoping to see grass growing in place of your moss, it’s not the moss’s fault. But you should probably take a look at your growing conditions if you want the grass to replace the moss.
Moss On Trees
Moss growing on trees raises another interesting question: if moss grows on trees naturally in forests, does that mean you can let it grow naturally on the tree growing next to your house?
In most cases, it’s probably harmless.
The only downside to allowing moss to grow uninterrupted on your tree is that it can add additional weight which the tree will need to support. If the distribution is uneven, it could throw off the balance of the tree.
This could be a problem if you know your tree is showing signs of falling over.
It can also cover up signs of tree diseases, in case that was something you were paying attention to.
Both of these problems really only become an issue if your tree is having bigger problems of its own. In that case, you’ll probably want to focus on dealing with the tree rather than the moss.
In my opinion, I don’t think it’s worth the effort to try to remove moss from your tree. The moss isn’t going to be causing any big issues for you like it would if it were growing on your roof or your gutters.
Moss On Your Walls
Moss growing on your walls may be an issue or it could be completely harmless depending on what material your wall is made of.
If it’s brick, concrete, or vinyl siding, moss is completely harmless. It can’t really do any damage other than messing with the aesthetic. Although, it can encourage fungal growth, which can eat away at your paint and structure.
If your wall is made of wood, on the other hand, moss could be a bigger problem. It could allow moisture to seep into the wood and cause rot. Although, the wood should be resistant to moisture penetration if it’s been treated.
In any case, regular exterior cleaning and repainting will remove it anyways. Washing the exterior once a year is a general recommendation. But you can have peace of mind knowing there’s no hurry to scrape it off unless you have wood walls (as long as there’s no mold).
Moss On Your Fence
Moss growing on your fence usually isn’t a cause for concern.
If your fence has been treated, it should be more resistant to moisture and resistant to moss growing on it in the first place.
However, its lifespan probably won’t be the best it can be if moss grows unchecked on it. Any time moss is growing on wood structures, it does increase the risk of mold growth and rot because of the extra moisture it holds onto.
Ideally, moss should be cleaned off, but it isn’t urgent. Most people would probably clean it off for aesthetic reasons rather than for the protection of their fence.
I’ve had some moss growing on my fence since my house was built over a decade ago and my fence is structurally perfectly fine with no signs of rotting.
Moss On Your Car
Moss growing on your car probably isn’t the first place you would expect to see it growing. But it can definitely happen if moss spores can find a small pocket on your car with the right conditions to settle into.
For most people, regular use and maintenance of their car will probably prevent this from happening since moss takes months to grow at the very least.
I live in the pacific northwest where there’s plenty of moss to go around and I’ve only seen moss grow on old cars that seem to have been left outside and untouched for years.
But if you’ve found yourself in a situation where you do have moss growing on your car, it can cause moisture seals on your car to degrade where the moss is growing.
It can also make it a little harder to open doors and trunks if growing in the wrong places.
How To Remove Moss
If you haven’t noticed already, if you’re wondering if you should remove moss, the answer is usually yes.
Now let’s talk about how to actually do it.
The annoying thing about moss is that can grow on all sorts of surfaces since it doesn’t have roots and doesn’t need soil. Instead of roots, it has rhizoids (root-like hair structures) which anchor it to its substrate.
This not only allows moss to grow almost anywhere (especially cracks and crevices), it also makes it harder to remove. This means that you probably won’t be able to get it all off with a quick spray of your garden hose or hope for a strong gust of wind to blow it away.
Usually, you’re going to need to scrape it off with a brush. And I’m not talking about that old toothbrush you’ve been saving in your bathroom for some reason. If you have a lot of moss to remove, you probably want to get a wire brush like this one I saw on Amazon.
Once you’re finished scraping the moss off, it’s a good idea to sprinkle some iron sulfate where it used to grow. Moss doesn’t like iron, while grass loves it. It will help prevent future moss from growing back while helping your grass turn green if you’re spreading it on your lawn.
It’s also a good idea to get into the habit of pruning plants and overgrown trees to increase the amount of sunlight around your home. This will discourage moss from growing because it prefers growing in shady, moist areas.
When Should You Call A Professional To Remove Moss?
Sometimes, calling in a professional to clean it off becomes necessary.
Usually, this is the case for moss growing on steep roofs, where removing it yourself can be dangerous and there’s a risk of damaging your roof during the removal. If you’re not careful or using the wrong tools, you can damage shingles or tiles.
It can also be worth it if you’re dealing with extensive moss growth that’s had free reign for several years. With more scope of work, it’s going to be more time consuming for you to take care of it yourself, while at the same time bringing the per-unit-of-work cost down to hire someone to do it for you.
It may also be worth considering if you find yourself having moss problems time and time again. In addition to probably doing a more thorough moss removal than a DIYer, a professional may be able to diagnose the cause and put in preventative measures to resist moss growth from coming back in the future.
It does cost more than doing it yourself, but in exchange for money, you’re saving time and getting reassurance that the removal is going to be done right.