Have White Mold on Houseplant Soil? Here’s What It Is & Simple Solution

Taking care of houseplants can quickly become an expensive hobby. Seeds, soil, equipment… the costs add up. Not to mention pots to put your plants in!

So it’s understandable if you’re peeved about white mold on houseplant soil. But don’t get frustrated. 

This mysterious substance has a simple cause and a simple solution. No, it’s not dust. And thankfully, it probably isn’t mold, either. 

It’s mineral buildup. We’ll use the TikTok garden guru @tannertheplanter’s video as a visual as we break this down.  

Image: TikTok @tannertheplanter

How To Remove Mineral Buildup In Houseplant Soil

Most plant parents water their houseplants with tap water, which contains a fair amount of calcium and other minerals. 

“We’re trying to will these plants to live out of their natural environment,” Tanner reminds us. “One thing we neglect oftentimes is remembering that these plants usually just grow with rainwater which is like liquid gold to plants.”

If you want to remove mineral buildup from the soil, try to replicate natural conditions by “flushing” the plant with pure water. 

Grab a jug of purified water when you notice a white, filmy material on the soil surface. Over the next couple of weeks, use this purified H20 to water the plant. Yep, it’s that simple. 

Remember, you’re not increasing the amount of water the plant receives. You’re just substituting tap water for water without the minerals. 

Overwatering your plants, especially houseplants and potted plants, can lead to root rot and other complications. 

If you notice a white fuzz on the outside of terracotta clay plant pots, that’s also mineral buildup. Removing mineral buildup from pots’ outsides is slightly more labor-intensive. And it’s something best done as a winter gardening chore.

That’s because it’s easiest to clean pots when they don’t contain any plants. 

Soak empty terracotta pots in a solution of roughly 1 part vinegar to 20 parts water. After a half hour of soaking, scrub the pot vigorously to remove the white powder. Finally, rinse the vinegar solution from the pot.

Want to avoid mineral buildup in the first place? Turn off the tap and permanently switch to distilled, spring, or reverse osmosis water. But the best thing to do- use rainwater. 

The Benefits of Using Rainwater for Houseplants

watering houseplants

Rainwater is often called “liquid gold” for plants and for good reason. It offers several benefits that can significantly improve the health and vitality of your houseplants.

Natural Softness

Rainwater is 100% soft water. Unlike tap water, it does not contain salts, minerals, or treatment chemicals that can build up in your soil over time. 

These residues can be tough on houseplants, especially in pots with more pronounced accumulation. Using rainwater can help flush these chemicals away and refresh the health of your soils, providing a more natural and beneficial watering solution for your plants.


Rainwater is rich in all the right things. It contains more Nitrogen and Oxygen than most tap water, nutrients essential for plant growth. Moreover, rainwater exposed to lightning has higher levels of nitrogen and ammonium, which are transformed into available plant supplies.

Ideal pH Level

Rainwater naturally has the best pH level for your indoor plants. It’s slightly acidic, ideal for most houseplants as it helps them absorb nutrients more effectively.

Conservation of Municipal Water

Using rainwater reduces the amount of tap water used to water plants and vegetable gardens, saving municipal water resources. It’s not only beneficial for your plants but also for the environment.


Rainwater helps to detoxify houseplant soil. Salts in tap water can build up in your soil and prevent growth. Hence, the white mold on houseplant soil question that brought you to this article. Rainwater, being free of these salts, helps to cleanse the soil and promote healthier growth.

If Not Mineral Buildup, White Mold on Houseplant Soil Could Just Be Dust

All this being said, sometimes, if it looks like dust… it might just be dust. Particularly if you’re noticing this substance on the leaves of your plant. 

When you purchased that elegant ficus, you might not have considered it a dust collector. But sure enough, like any other surface left unattended for long enough, plant leaves collect dust. 

But unless you’re trying to rid your house of dust bunnies, you don’t need to worry about dusting your houseplant. Right? 

Not exactly.

In small amounts, dust particles on leaves won’t harm plants. However, a thick enough layer of dust could impede your plant’s ability to perform photosynthesis. 

How to Dust a Houseplant

dusting houseplant

So how do you dust a houseplant? The answer is: very gently. 

Skip the furniture polish. Instead, dampen a cloth with warm water. You can add a natural leaf-shining solution or a diluted amount of dish soap if you’d like. But a bit of water will work as well.

Then, carefully rub each leaf with a damp cloth. You’ll save yourself a lot of work by starting from the top of the plant and dusting your way to the bottom. 


@tannertheplanter Mineral buildup would have to be quite severe to cause houseplant decline, but any stress we can take away from the plant is a plus in my book! #planttiktok #planttok #planttips ♬ original sound – Tanner Mitchell
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Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.