Why is Mold and Mildew Growing on My Expensive Teak ____ (fill in the blank)?

Without a doubt, I receive more emails and messages about mold and mildew than any other topic.

When someone notices mold or mildew (yes, it can be difficult to tell them apart) on their teak, their first thought is:

“Maybe it’s not real teak!” Because teak is supposed to repel mold and mildew.

Their second thought is:

“How do I get rid of it?”

But before we go there, I’ll give you a quick cheat sheet on how to tell whether you have mold, mildew, or both, on your teak.

Mold has a fuzzy, somewhat raised appearance, and in unaired areas it has a strong, musty smell.

It often appears in dark shades of black, green and even red. 

Mildew has a powdery appearance that may also have a distinct, foul odor. 

Mildew is typically gray, white or light brown in color and generally rests flat on the surface of a moist area—and it's actually produced and lies atop mold.

So, can mold and mildew really grow on teak?

No! And Yes!

Quality teak, rich in oil and silica (typically Grade A or B teak), is absolutely mold- and mildew-proof.

By itself, good quality teak will not attract or develop mold and mildew.

Ok... so what do I mean when I say: by itself.

Well, you may have the most expensive and highest grades of teak; and yet, you may find one day that it’s developed mold and mildew.

Why? Well, the reason, or the culprit, is not the teak. 

It’s what's on the teak.

It’s what you’ve left behind on your teak—that’s growing mold and mildew. Not the teak itself.

The teak shower mat shown below provides the perfect example...

The photo shows the bottom of one of our teak shower mats sent to us by an irate customer who claimed that our mats are not made of real teak.

He sent us this photo showing all the mold and mildew growing on it.


He even parotted, what I often state ad nauseum, that mold and mildew will not grow on teak.

However, he left out the qualifying part: “by itself.”

Let me affirm what is eminently obvious:

Teak will not clean itself!

Accordingly, I wrote back to him and told him that he’s a complete idiot, and a disgusting slob!

No!! Of course I didn’t say that. I was very gentle. And I tactfully pointed out to him the following:

Your photo shows there is definitely instances of mold (the black splotches) and what might even be mildew, but…

All that white powdery looking film all over the bottom, and even on the rubber feet—that’s neither mold nor mildew—it’s soap scum, and who knows what else.

Including, (look closely at the photo) strands of hair.

Bottom line: if you don’t rinse off and clean your mat regularly, mold will absolutely feed and grow on what you left behind: soap scum, hair, shampoo, lotions, oils, and whatever else you used while showering.

The same applies to your other teak items, whether they be outdoors or indoors.

Obviously, soap scum, shampoo, etc. will not accumulate on your teak patio furniture or teak dining table.

But dust, food, spilt liquids and other accumulations will provide a great feeding ground on which mold and mildew will grow and thrive.

Ok, so now you know why there might be mold and mildew on your teak.

Now on to the remedy when mold and mildew are present.

How to remove mold and mildew from your teak

What follows is brief overview of what you’ll read in our Teak Care Guide

For comprehensive instructions on how to restore your teak to its original, just bought gleam and shine read our Teak Care Guide.

If the mold is barely visible, soap and water and a soft brush or sponge will often do the job.

If it’s a more serious infestation, bleach will kill it, and ammonia will remove the stain. Never ever mix the two together! And scrub the area with a stiff bristle brush.

A second option is to use oxalic acid (an organic compound found in vegetables).

There are also commercial 1-part and 2-part cleaners that you can try (these are mentioned in our teak care guide).

Lastly, when all else fails, you’ll have to sand the teak and then re-treat the wood (various products from oils to sealers are also found in our Teak Care Guide.

IN CONCLUSION: don’t throw out your teak—no matter how old, neglected and nasty it looks!

You can restore almost any teak to showroom quality. Yes, it may require a bit of elbow grease—but it’ll be worth it in the end!

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