The Hidden Dangers of Mold Growing on Your Crawl Space Soil

That fuzzy growth on your crawl space soil isn't just "dirt being dirt" – it's a potential health hazard silently affecting your home and family. Most homeowners don't realize that the perfect mold habitat exists right beneath their feet, with all five essential growth factors readily available.

Clay soil in your crawl space acts like a nutrient-rich refrigerator for mold, storing organic matter and vital minerals while holding moisture like a sponge – up to 55% by volume according to Cornell University research. Combined with adequate oxygen and the comfortable 60-80°F temperature your home maintains year-round, it's no wonder mold flourishes in this hidden environment. Within just 24-48 hours, mold begins its growth cycle, becoming visible within three weeks and continuously releasing spores and mycotoxins that can infiltrate your living space.

The health implications shouldn't be ignored. These microscopic invaders can trigger allergic reactions, exacerbate respiratory conditions, and gradually weaken your immune system through prolonged exposure. But before you grab a shovel to remove that moldy soil, stop! Disturbing contaminated soil triggers mold's defense mechanisms, sending spores airborne to colonize new areas of your home. Instead, professional remediation through proper waterproofing, encapsulation, and dehumidification creates an environment where mold simply cannot thrive. Your crawl space deserves professional attention – not just for your home's structural integrity, but for your family's long-term health and wellbeing. Ready to address that moldy soil properly? Check out my comprehensive guide to crawl space repair and protect what matters most.

Playlist mentioned in video: https://www.youtube.com/playlist?list=PLxsYiAum9ovwBw3L_-MD37h2rGoh4ho3p

Chapters

• 0:00 Introduction-Is mold on crawl space dirt bad?
• 0:32 5 things mold needs to grow
• 1:04 Is soil a mold food source
• 1:59 Is soil wet enough to grow mold
• 2:34 Does soil contain oxygen to support mold
• 3:07 Is soil temperature adequate to grow mold
• 4:12 How much time is needed for mold to grow
• 5:33 Is soil mold harmful
• 6:44 Book-Crawl Space Repair Myths Busted
• 7:13 Should you remove moldy soil in crawl space
• 8:03 What should be done about moldy soil in crawl space

Transcript

Speaker 0: 0:00

Hey there, michael Church with Crawl Space Ninja. Have you ever looked inside of your crawl space, looked down at the dirt and saw mold growing on the soil of your crawl space? Should you be worried about this? Is this dangerous or is it just dirt being dirt? Today, we're going to answer that question. Is mold growing on the soil of your crawl space something to panic about or just ignore and stick around to the end of the video, I'm gonna share what you should do if you find mold on the soil of your crawl space.

Speaker 0: 0:33

Let's get into it. First of all, you need to understand that mold needs things to grow, not only in your crawl space, but in other parts of your home. Number one mold needs a food source, it needs moisture, it has to have oxygen, as well as suitable temperature and, of course, time. If you give mold these five ingredients, boom, it's a party in the crawl space. So let's take a look at each one of these individually and how soil relates to each one of these as well. So is the dirt under your crawl space a smorgasbord for mold? Well, surprisingly, yes, it is, especially those clay-rich soils that many homes built on crawl spaces have. But what's interesting is, according to soil scientists, mold doesn't grow directly on the clay. But here's the twist Clay holds nutrients and organic matter that mold loves. Think of clay as a refrigerator. It stores the leftovers for molds to snack on. Plus, clay soils have a high cation exchange capacity, or CEC that's a fancy way to say that. They attract the vital nutrients that mold needs. These nutrients include calcium, potassium and magnesium, all of which support microbial growth. And, yes, mold is a microbial.

Speaker 0: 1:58

Okay, so we determined that soil is a food source, but is soil wet? You better believe it, especially clay soil. It's like a sponge. Unlike sandy soil that drains rapidly, clay soil holds water for days or even weeks at a time. According to Cornell University, clay soil can hold up to 55% moisture by volume. That's like walking on a wet sponge every time you're under your house. In short, if you have clay soil in your crawl space, you have moisture in your crawl space, which is a green light for mold to grow.

Speaker 0: 2:34

So the third ingredient is oxygen. Does soil have oxygen, you bet. Unless it's completely waterlogged or compacted, the air between soil particles contains oxygen, nitrogen and carbon dioxide, all of which is like the air around us, and scientists say that mold breathes as well, well sort of. It absorbs the oxygen in order to help it grow. And not only does that oxygen help it grow, it helps it spread to other areas of the home.

Speaker 0: 3:06

But what about temperature? Mold does need the right temperature to grow and most crawl spaces hit that sweet spot all year long. Mold typically thrives in temperatures between 60 degrees Fahrenheit and 80 degrees Fahrenheit, but some molds can survive in freezing temperatures, like in the Arctic and Antarctic regions, as well as very high temperatures, like in the Arctic and Antarctic regions, as well as very high temperatures, like in jungle regions. In cold weather, mold spores can or may go dormant, but that doesn't mean they're dead. They're just sitting there waiting for the temperature to rise and for that moisture that's trapped in that clay soil, along with all the nutrients, so that it can thrive and survive. As I mentioned before, there are even Arctic molds and desert molds, so molds can pretty much thrive anywhere in the world. So don't let the seasons fool you. Just because it's winter outside doesn't mean that mold isn't growing in that crawl space, because I guarantee you the heat from your HVAC system is keeping that crawl space warm enough for that mold to spread and grow.

Speaker 0: 4:10

Lastly, is time. This one usually does not come up when you look at what does it take for mold to grow, but I wanted to throw one. Usually does not come up when you look at what does it take for mold to grow, but I wanted to throw this one in there just to give you a little bit of education of how long it takes for you to visibly see mold growing in the soil or perhaps on the joists of the crawl space. Mold can start growing in as little as 24 to 48 hours. Usually this would occur after a water event or high humidity, but, as we mentioned before, soil traps a lot of water. It could take anywhere between 18 to 21 days for the mold to become visible. This is what's called the fruiting body. It's sort of like if you're walking in the woods and you see a mushroom growing on the ground. Well, the mold was growing in the soil before the mushroom showed up. So if it takes 24 to 48 hours for mold to get started, you could possibly see it within 3 to 12 days, but most scientists agree it takes between 18 to 21 days for mold to become visible. And don't forget mold colonies can spread extensively and become more noticeable the more moist the crawl space is. Factors like types of mold, the surface it's growing on and the surrounding temperature and humidity can also influence the exact time it takes for mold to become visible.

Speaker 0: 5:33

Now let's get into the health question. Is mold on dirt actually dangerous? The answer is potentially yes. You see, mold spores can go airborne, especially from the dirt in a crawl space. If the crawl space soil isn't sealed away from the rest of the crawl space, you might not even see the spores. As I mentioned, most mold spores are microscopic, but that doesn't mean they're not looking for a new place to grow, like inside the HVAC system or on the joist of the crawl space, or maybe even in your living space. Some molds can cause allergies, while depending on the immune system of the person, it could be more extreme Like COPD or even asthma can occur in people with weaker immune systems. And let's not forget the mycotoxins. It's sort of like an off-gassing of the mold, and the longer you're exposed to mold, the more attack it does on your immune system and the weaker your immune system becomes.

Speaker 0: 6:33

So if you know that you have mold in your crawl space or in your living space, you should address it immediately. Don't wait and if you need help with that, of course Crawl Space Ninja can help. Speaking of help, I want to take time to introduce you to my book Crawl Space Repair Myths Busted. Whether you have a crawl space, basement or you live on a slab house, this book has a lot of great information about mold and moisture. So if you want to be armed with good information to protect yourself from making a bad decision, I recommend you pick up crawl space repair myths busted, available on amazon in both the printed and audible formats.

Speaker 0: 7:12

Okay, so you might wondering should you remove that moldy soil? Honestly, that's a pretty bad idea and here's why Mold has a natural defense system and if you go in there and start digging out that soil, you're just going to cause that mold to enter fight or flight mode, and typically it's going to flight, which means it's going to go somewhere else and land and it's going to try to find moisture either on the joist, the subfloor behind the insulation inside the HVAC system, or make its way through the penetrations in your subfloor right into your living space. So I don't recommend removing the soil because even when you do remove the soil and you put new soil back in, the old soil is going to expose mold to the new soil. So what should you do?

Speaker 0: 8:03

What we always recommend is an interior waterproofing system with sump pump, along with encapsulation and dehumidification, and I know what you're thinking. Wait a minute, michael. You said not to disturb the soil. Well, as we are digging that soil out, we're going to have a fan blowing the to disturb the soil. Well, as we are digging that soil out, we're going to have a fan blowing the air out, so that way, if any of that mold trapped in the soil becomes airborne, it has a place for it to go outside of the crawl space and keep it from getting inside of the home.

Speaker 0: 8:28

But installing that interior French drain and sump pump system is going to minimize the amount of moisture in the soil. And then you lay the plastic down over that soil to help separate the soil from the air of the living space. You keep the humidity down with your dehumidifier and it should keep the mold from growing and spreading inside the crawl space. So, in summary, mold growing on the crawl space dirt could be a big deal and you shouldn't ignore it, but you shouldn't go in there and start digging the dirt out. As a matter of fact, if you want to learn more about what to do. I'm going to put a playlist of the crawlspace repair challenge that we did. That covers everything from the inspection to the final product, so make sure you check out that playlist and I'm Michael Church with Crawlspace Ninja. Hope you make it a happy and blessed day and we'll see you later.