How to Propagate Plants in a Petri Dish

Sterilize the petri dish before putting anything into it. This can be done by cleaning the dish with a soft cloth with antibacterial soap and warm water. After rinsing the dish, put the dish into a solution of 1 part bleach and 9 parts water (e.g. .1 cup bleach with .9 cup water) for two minutes. Dip petri dish into alcohol for just a second and then place on a sanitary surface to allow it to dry. Make sure to use sterile equipment when moving the dish out of the liquids. This may be unnecessary if you have a plastic petri dish still in its bag as these are sterilized when packed.

Check that your water has a pH of 5.5 to 6.5. If it is lower than 5.5, gradually add baking soda to the water until its pH is between 5.5 and 6.5. If the pH is higher than 6.5, gradually add lemon juice until the pH is in the correct range. Once the pH of the water is within range, soak your growing medium in the water, ensuring full saturation.

Cut a leaf bud from your plant. This must be done carefully. Use the knife to cut through the shoot at a 45-degree angle. This should be a straight cut done right above the bud on the leaf axil. Make sure to pick a leaf bud that will ensure once this cut is made, there is a 5-inch stub still attached to the bud.

Place your moist plant medium into the sterilized petri dish. Before placing the leaf bud into the medium, dip the underside of the stub of the bud in the rooting hormone. Place the bud into the growing medium in your petri dish. You can put more than one bud into the dish to increase the chances of propagation, but do not crowd the dish with buds as they will use up the nutrients in the dish too quickly.

Place a plastic cover onto the petri dish. Provide the dish with an adequate amount of light and warmth. For the first two weeks after putting in the leaf bud, the dish should be in a temperature of 60 to 80 degrees Fahrenheit. Ensure that the plant medium stays moist, using the same pH balance of water that was used to soak the medium. As soon as new shoots or roots form in the dish, remove them and put them into a flower pot to continue to grow, even if they sprout before the two-week period is over.