How to Test for Black Mold in Your House

Mold is not only a common, unsightly problem in homes, but it also can also be harmful. Black mould can cause allergy symptoms to act up and aggravate those suffering from asthma. Home testing kits can help you gain control over mould and mould spores in your home. Mold testing kits can be purchased at local department and home improvement stores. Most home testing kits operate in the same way. The kit will include a petri dish to collect the sample in. Before you begin the process you will need to set the petri dish up by removing it from the packaging and pouring the mould medium into the petri dish. The mould medium will need to harden in the bottom of the dish for one hour. After the allotted time, continue with the mould testing process by choosing your method of mould sample collecting.

Swab the area that is infected with black mould. The mould testing kit includes a sterile swab. Use the swab to collect the black mould sample. Wipe the swab across the mould, and make sure the mould adheres to the swab.

Remove the lid off of the petri dish.

Wipe the swab that you just use to collect the black mould sample across the bottom of the petri dish. The mould must stick to the inside of the petri dish.

Secure the lid onto the petri dish, and follow the instructions included with the kit on how and where to send the mould sample.

Remove the lid off of the petri dish.

Place the petri dish on a level location in the middle of the area you want to test for black mould.

Allow the petri dish to sit in the area undisturbed for one hour.

Replace the lid back onto the petri dish, and allow it to incubate for 48 hours. Check for signs of black mould growth at the 48, 72 and 96 hour marks. If there are no signs of black mould growth, discard the dish. If black mould growth is present, send the sample to the lab for processing.

Remove the lid from the petri dish.

Tape the open side of the petri dish to an open air vent, and close the other air vents connected to your system.

Turn the system's fan on high for 10 minutes.

Remove the petri dish from the air vent, and secure the lid.

Allow the dish to incubate for 48 hours. Check the dish at 48, 72 and 96 hours for signs of black mould growth. If mould growth is present, ship the sample to the lab for processing, If no mould growth is present, discard the petri dish.


Depending on the brand of black mould testing kit, you may have to pay a small fee for the lab to process your sample. For more information, consult the instructions included with your testing kit.

Things You'll Need

  • Home mould testing kit
  • Tape
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About the Author

Amanda Flanigan began writing professionally in 2007. Flanigan has written for various publications, including WV Living and American Craft Council, and has published several eBooks on craft and garden-related subjects. Flanigan completed two writing courses at Pierpont Community and Technical College.