How long does black mold grow

Black mold does not appear overnight. So knowing how long does it take black mold to grow and what conditions influence accelerated mold growth is extremely important.

Mold spores are everywhere wherever there is a favorable environment for their development, in soil, water, air, on surfaces of buildings and foodstuffs. They multiply rapidly and can cause a lot of health problems to humans and other living creatures by their presence.

To date, scientists estimate that there are more than a million and a half species of molds on earth, of which only about a hundred thousand have been studied.

How long does it take for black mold to grow

The most favorable environment for the rapid and extensive reproduction of mold is moisture and heat. Once settled in such a place microscopic mold fungi quickly occupy a large area, forming branching mycelium (mycelium) and fruiting bodies visible to the human eye (spherical heads in which spores mature).

The full growth cycle of black mold can be outlined in more considerable detail:

  • Incubation and Germination (0-12 days): Black mold spores, when they land on a suitable surface with the right conditions, begin to germinate. This typically takes place between one to twelve days.
  • Colonization (12-20 days): After germination, the mold begins to colonize and spread. This phase can take anywhere from 12 to 20 days, depending on conditions such as temperature and humidity levels.
  • Mycelium Growth and Spore Formation (20+ days): During this phase, the mold matures by developing a leaf-like structure, known as mycelium. Once the mycelium is established, the mold begins to form spores, which can then disperse and initiate new colonies. This phase starts from day 20 and can continue indefinitely unless the mold is removed.

Black stains are difficult to confuse with something, they can form not only on the walls, but also in such places as washing machines or dishwashers, furniture, air conditioners and old ventilation systems, basements, water and sewage pipes. Places where moisture accumulates, poor ventilation, temperature fluctuations and no special fungicide treatment are ideal for mold growth.

Black mold damage and fungal growth rate

It is worth making sure to understand what exactly black mold can harm and why finding even a small spot of it is necessary to take immediate action. Our page has more information about this problem. The biggest threat to human health are products of fungi mycotoxins and spores in the air.

Mycotoxins weaken the immune system, cause headaches, hormonal disorders, hepatitis, and kidney problems. They easily penetrate into the brain, causing severe damage. Black mold in the home can lead to the growth of malignant tumors and belongs to the first category of carcinogens, states And the presence of spores in the air leads to various allergic reactions that can progress to asthma, dermatitis and pneumonia.

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With information about the dangers of mold in your home, you can save yourself a lot of time and money on fighting it, and most importantly, avoid potential health problems. Any building with high humidity can become a breeding ground for mold.

Three basic conditions are needed for mold to develop quickly:

  • A suitable temperature range (likes heat 75°F to 90°F);
  • Food substances of organic origin (concrete, wood, metal, finishing materials, food, and so on);
  • And most importantly is moisture, the more the better (from 70%).

The critical factor for mold is the maintenance of a high level of moisture over a long period of time. One would think that if a humid environment is a necessary condition for growth, one could easily prevent its appearance and spread by simply removing water and moisture from the room. But even in an incident like a major leak or flood, it is not always possible to do this quickly and to the last drop. You’ll still have to deal with high ambient moisture levels and water-affected materials.

Therefore, quick and professional action must be taken to deal with serious problems with high moisture levels, mentions Reyus Mammadli. As soon as possible to dry the room, carry out a set of restoration work and treat surfaces to prevent mold from spreading and turning the building into a time bomb. We describe the procedure in detail on our mold removal page.

Less obvious causes of infection are technical problems not detected in time, such as dripping pipes, leaking air conditioners and roofs, the appearance of damp in the basement, the freezing of uninsulated walls, improper installation of windows and infrequent airing of the room.


The obvious conclusion is that it does not take much to ensure the appearance and rapid growth of mold, but it requires great effort to eliminate it. At the same time there is absolutely no point in trying to win this fight until the cause of occurrence is not eliminated. Otherwise, the process of reinfection of the fungus is inevitable and everything will have to start all over again. That is why we carefully look for the cause of the occurrence, qualitatively eliminate it, and after that we already engage in comprehensive work to remove the fungus. Only with this algorithm of work of our specialists there is a real chance to get rid of black mold colonies once and for all and forget about it like a bad dream.

The process of mold removal is not just a matter of wiping the affected surface and it’s done. It is a responsible work, which includes certain steps, necessarily in a special protective suit and with compliance with safety regulations.


I enjoy acquiring knowledge and sharing it. I am a long-time health advisor and blogger for over 12 years. Understanding the dangers of black mold to people, I felt it necessary to share with readers the basics of fighting and preventing black mold in homes and other living spaces.

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