How to Grow Bacteria in Agar Petri Dishes
- 1). Keep the agar petri dishes stored upside down in a refrigerator until you are ready to use them.
- 2). Remove the agar petri dishes from the refrigerator and let them warm up to room temperature. It normally takes about one hour for them to warm up.
- 3). Remove the lid of the petri dish and press the agar against any surface. If you cannot hold it directly against a surface, you can use a cotton swab. Rub the cotton swab against any surface and press it gently against the agar.
- 4). Put the lid on the petri dish and tape it shut with masking tape. Label the tape with a marker to keep track of the bacteria source.
- 5). Place the petri dishes in an area that has a constant temperature of roughly 100 degrees F. The dish should be away from direct sunlight, so an incubator is ideal.
- 6). Observe the petri dishes daily. Bacteria colonies should begin to grow within a couple days.
- 7). Pour a small amount of bleach on the petri dishes before you discard them to kill the bacteria.