How Fast Does Mold Spread?

How Fast Does Mold Spread?

“How fast does mold spread” It’s a question our team gets all the time.

If you are like most homeowners, Mold in your home can be a scary situation.

If you are wondering how many homes are infected with mold, the answer is around 70%

In fact, there’s an interesting article that goes over other mold statistics by Comfy Living, if you are interested in learning more about how mold can affect you.

The spread of Mold is all about catching the growth before it is too late.

Otherwise, you will have to call a team like ours to perform a mold removal procedure. (We don’t mind the call though, giving you peace of mind is what we love to do.)

With all of this in mind, lets deep dive into the question “how fast does mold spread?”

“How fast does Mold spread?” The Answer: It Depends!

Answering “how fast does mold spread?” is not as easy as you might think.

How fast mold spreads depends on how that species of mold grew in the first place. To really understand how fast a species of mold can spread, let us look at the four factors necessary to cultivate Mold growth:  


The ideal temperature for Mold growth is between 77 and 86 degrees.

While some mold species can grow below or above that temperature, most mold species cannot grow when temperatures drop at or below 40 degrees.

There may be a varying range in the temperature in which Mold can grow if the air is more humid, however, under normal conditions the ideal temperature for Mold growth is between 77 and 86 degrees 


No matter how warm the temperature may be, there is no exception that Mold needs water to grow.

Mold flourishes under humid, wet, and/or damp conditions.

Therefore, it is important to prevent circumstances like water damage as these events promote an exceptional amount of Mold growth. Without water, Mold cannot grow.  


Mold is a bacterium that can only live in the presence of oxygen.

Species of Mold use a process called cellular respiration which utilizes oxygen to metabolize substances, such as sugars and fats, to obtain energy.

Oxygen is necessary for the growth and spread of Mold.  


Mold VS Mildew

Without a surface to grow on, Mold cannot grow.

While it can still spread as Mold utilizes oxygen to spread, if a surface such as food, wood, drywall, even dust and metals, are not present, Mold cannot land and therefore grow.


The last and final piece of the puzzle regarding how quickly Mold can spread is the species of Mold.

Some Mold species spread faster than others, some spread slower than others.

For example, Stachybotrys, thrive on surfaces such as cardboard and while they spread slowly, Stachybotrys. can spread in exceptionally enormous quantities 

Overall, there are over 100,000 varied species of Mold, but as a homeowner, there are 2 types of Molds that you may come across: 

  • Slow Growing  
  • Fast Growing 


Slow Growing:  

The most common slow-growing Molds that you will see as a homeowner are Acremonium, Alternaria, Aspergillus, Cladosporium, Fusarium, Stachybotrys, and Trichophyton.

These types of Molds can take weeks to even 6 months and beyond before they start growing and spreading.

For example, Stachybotrys, also known as toxic black mold, typically colonizers within eight to eleven days after it lands on a surface.

This could mean that your home could be affected by this type of Mold before the first sign (after eight days) appears.


Fast Growing: 

The other category of Mold is fast-growing Mold.

The most common fast-growing Molds that you will see as a homeowner are Mucor, Penicillium, Rhizopus, and Trichoderma.

These types of Molds grow at such rapid rates that under the correct conditions, species such as Trichoderma, can grow at 2cm/day.  

While there are varied species of Mold that grow faster than others, such is the case with Stachybotrys and Trichoderma, the most important consideration is the condition with which the Mold is under.

The conditions in which the Mold is allowed to grow are the biggest promoter of how fast Mold expands.

For example, Bread with high moisture content grows Mold the fastest (remember the four conditions Mold must have to grow.)


“How fast does Mold spread” A General Mold Growth Timeline:

Mold spread on a surface

The timeline for Mold spread varies, however; now that we know what types of Molds spread slowly and what types of Molds spread quickly, we have a better understanding of the timeline of Mold spread.  


How fast does mold spread: A general timeline for fast-growing species:

The first species of Black Mold in the fast-growing family is Penicillium.

When Penicillium lands on a surface, it can grow 4-5cm within 10 days.

Penicillium uses building materials such as wood and drywall as well as soil for nutrients in the growth process.

Comparing the growth of Penicillium to the growth of Mucor, Mucor grows at a rate of around 2cm every 3-5 days before hitting dangerous or unsalvageable for restoration. 

Other types of fast-growing Molds such as Rhizopus can spread within a few days given the temperature and other conditions are just right. On the same timeline as Rhizopus is Trichoderma.

Trichoderma can grow and fully mature to the point of spreading within a few days.  

While on average fast-growing Molds spread 2cm a day, they can spread even wider and faster if they are under the right conditions such as water levels, temperature, nutrient supply and more.  


How fast does mold spread: A general timeline for slow-growing species:

On the slow-growing timeline of Mold, the changes are vastly different.

For example, Acremonium has high levels of toxicity and grows at most 2.5cm every 5 days.

When compared to Acremonium, an even slower Mold is Fusarium. The incubation period for Fusarium is 2-6 months.


How Fast Does Mold Spread?

The growth and spread of Mold vary greatly depending on the species of Mold and the conditions that the Mold is in, however, one thing that does not vary is that when you spot Mold, it’s important to act quickly to stop the spread and mitigate risk to health or home damages.  

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