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Mold and How it Grows

by Jonathan

What is Mold?

Mold is a term used generally to describe a group of organisms that appear as fussy or powdery growth. Molds the same with rusts, yeasts, and mushrooms are different members of the fungus family.


They were once considered as a part of the plant kingdom, fungi are now regarded as their own kingdom of organisms. Molds live off by absorbing nutrients from dead or living organic matter.

As of date, Mycologists have identified at least 100,000 living species of fungus have been identified, some of which are beneficial to mankind. An estimated 200,000 types of fungi are in possible existence which has not yet been identified.

What Does Mold Do?

Molds serve an important role in nature. They help break down organic matter that other animal or plants cannot. Aside from nature, humans also have found uses for mold.

We eat molds in our cheese, soy sauce, yogurt, wine and beer, mushrooms, dried fruits such as prunes and raisins, vinegar, foods containing yeast, soy sauce, mayonnaise, other salad dressings, catsup, chili sauce, canned tomatoes, canned juices and so much more.

Humans also found out that the best use for molds, as antibiotics to cure disease. The best example of this is Penicillin, which is derived from the mold Penicillium.

Where Can Mold Grow?

Mold can almost grow anywhere, be it indoors or outdoors, as long as there is enough surface moisture to sustain their growth keep them alive.

They can be found in all sorts of climate and in every social and economic condition. They thrive where moisture, oxygen, and the chemicals they need are present.

They can be found on the surfaces of objects, within pores, and inside deteriorated materials.

Indoor Molds

Indoors, molds can be found in damp basements, in poorly ventilated closets, and behind baseboards and walls. They thrive in bathrooms, hot tubs and Jacuzzis, the laundry room especially dirty clothes.

They can be found in kitchens and food storage areas, even in the refrigerator and its drain pan. Dirty dishes are a common place for molds, soiled trash cans and compactors.

Mold can also be found in mattresses, any moist carpets or rugs, and in heavily draped or double-paned windows. Worn clothing and leather products also have a high possibility of contamination of molds.

Roof or plumbing leaks and unsealed concrete slabs is a good bet for having mold.

Additionally, the stalks and leaves of indoor house plants, along with the dirt they grow in, can support mold growth.

Outdoor Molds

While outdoors, molds are easily found on dead and dying vegetation such as leaves, straw, grain or other crops, and wood. They are also common in moist, shady areas, and in certain grasses and weeds.

They sometimes grow in soil or on debris and other surfaces as long as there is continuous exposure moisture. They can be found on the leaves of shrubs and other plants that grow against a house or in standing water.

In gardens, molds thrive in compost piles since they have both moisture and humidity. Some molds attach themselves to grains such as wheat, oaks, and corn, making farms, and silos probable places to find them.


Neglected gutters around the house and poor drainage of foundation water are a very good breeding ground for mold growth.

How Does Mold Survive?

Molds are very fit for survival. Though, in order to thrive, molds need four things.

4 Things Mold Needs to Thrive

  • food
  • a fungal spore
  • moisture
  • warmer temperatures [40-100 degrees fahrenheit]

Molds have no problem when it comes to food since they can eat any organic material present.

When the temperature and moisture in the environment are suitable for germination, the fungus spore bursts and grows into a thread-like filament which contains the fungal spores.

Liquid water comes into the house through leaky foundation or from leaks or breaks in plumbing. These conditions are the main cause in the formation of indoor organic materials.

If left for more than one to two days, these conditions allow mold growth to commence.

Mold Thrives in Humidity

Molds can thrive on places were the average humidity is between 40 degrees Fahrenheit to 100 degrees Fahrenheit. Humidity indoors is a direct result when hot air comes in contact with a cool surface and water condenses to form dew.

This is a typical setting in buildings that have poorly insulated exterior walls and windows during winter. Exposed cold pipes in the summer can also produce this same effect.

Further Recommended Reading :

Joslyn from the MoldBlogger Team

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1 comment

Peter January 7, 2012 - 1:39 pm

This answer even though it was 2006 was very helpful. You save me a trip to the Matt, and saved me a loss of $$$.


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