How to Test House for Mold With Petri Dishes

Decide on the area of the house you want to test. You can test the air in a room or enclosed area, such as under the kitchen sink, air conditioner vents or swab a sample of mold growth.

Wash your hand before handling the test kit. It is important to keep your testing as sterile as possible to avoid contamination of your sample.

Gently shake the bottle with the growth medium, and pour into the petri dish. Gently move the growth medium inside the plastic container so it covers the surface evenly.

Place uncovered on a flat surface, and wait an hour for it to settle and harden.

Put the plastic uncovered petri dish in the area you want to test for one hour (if testing air). You can also test the air coming out of an air conditioner vent turning on the air conditioner and placing the petri dish directly facing the vent you want to test for 10 minutes. For a swab sample, take a sample of the mold growth with the sterilized Q-tip, and gently swipe over the growth medium.

Put on the lid, and leave undisturbed for the next 24 hours.

Check for any growth after 24 hours and again at 48, 72, 84 and 96 hours. Some molds take longer to develop.

If there is growth, follow the instructions to send the specimen to the lab so they can tell you what kind of mold growth you have in your home. They usually ask for the date the specimen was taken, what area the sample was taken and ask for a form of payment.