How Fast Does Black Mold Grow?

by | Nov 15, 2022 | Black Mold, Mold and Infants, Mold Inspection

Mold can be a severe problem in homes and businesses. Not only is the mold unsightly, but it can cause health problems for people who breathe in the spores.

One of the dangerous types of mold is black mold. Also professionally known as Stachybotrys chartarum, black mold produces mycotoxins, which can cause serious health issues.

Black mold grows in damp, humid environments and can appear as greenish-black or black spots.

Read more: What Causes Black Mold?

It’s essential to understand how fast black mold grows on concrete and other surfaces so that you take the necessary steps to prevent it from taking hold in your home or business. Black mold usually starts growing in ideal conditions in 24 to 48 hours. We will also discuss health issues with black mold and factors that influence mold growth in your home or business.

What Are the Health Issues With Black Mold?

Black mold, known as Stachybotrys chartarum or Stachybotrys atra, is a fungus that can cause serious health issues if left untreated. These include:

  • Respiratory problems, including coughing and sneezing, asthma attacks, and chronic sinus infections.
  • Eye irritation, such as burning eyes or watery eyes.
  • Skin problems, with redness and itching being the most common symptoms.
  • Various neurological issues, such as headaches and fatigue.
  • In extreme cases, black mold can cause nausea and vomiting.

Patients with weakened immune systems, as well as infants, children, and older adults, are especially vulnerable to its effects.

Factors That Affect How Fast Black Mold Grows

Mold only needs a few essential components to grow and thrive: moisture, warmth, food source, and oxygen. Here are the factors that can affect how quickly black mold grows:


Mold will grow faster in moist, humid environments. High relative humidity (RH) means more moisture is available for the mold to feed off, causing it to grow faster. Places like bathrooms and basements are typically more humid, making them ideal environments for mold growth.


Warm temperatures help black mold reproduce quickly. The warmer the environment, the faster it will grow. Locations with higher temperatures, such as attics, will experience faster mold growth than rooms with lower temperatures.

Food Source:

Different molds require different food sources to survive. Black mold grows on organic materials like wood and paper high in cellulose. To grow faster, it needs a consistent source of these materials.


Mold needs oxygen to survive and reproduce. Without it, the mold won’t be able to grow. Black mold can also reproduce anaerobically (without oxygen) in small amounts, substantially slowing its growth.

What Should You Do While Waiting for Mold Remediation Services?

If you have noticed telltale signs of black mold in your homes, such as discoloration, musty smells, and even health issues, you may:

a) Seal off the area until a mold remediation service arrives

b) Contact your insurer and file a claim

c) Increase ventilation in the affected rooms to reduce moisture levels

d) Clean up any remaining water or spills and all porous materials (like carpeting and drywall).

Contact Mold-B-Gone for expert mold inspection in Atlanta. We have a team of certified professionals available to answer any questions about mold growth, particularly black mold.

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