Plastic Petri Dishes

 Petri dishes can culture molds or bacteria or act as a small enclosed environment for insects and plant seedlings or even as a display case. These petri dishes are made from clear polystyrene and are sterilized. 

We do not supply them with agar but gelatin ("jello") can be used instead although it liquifies around room temperature. 

A simple recipe for nutrient agar to grow bacteria would be:

• 0.5% powdered milk or whey protein concentrate
• 0.3% beef extract (beef bouillon cubes)
• 1.5% agar

% means weight by volume. In other words, if you have 1 litre of water (1000g), add 5g of powdered milk, 3g of beef extract (or ~1/5 of a bouillon cube) and 15g of agar. Mix & heat in a pressure cooker to sterilize, then pour into the petri dish, close the lid & let cool down.