1 A do-it-yourself approach for basic basement steps starts around $250-$350 for materials, and takes about 3-4 hours. 2  That's with standard lumber, such as pine; costs can go much higher with more expensive wood, such as oak.
Pour enough melted agar into each sterile plastic petri dish to cover the bottom - about 1/8 to 1/4 deep. Replace the lid immediately. Place agar plates on a counter top to cool and set. Agar medium will set like stiff gelatin at room temperature. The agar medium is now ready for storage or use.
Incubation of agar plates [edit]. Plates are incubated upside down to prevent drops of condensation collecting on the inoculated surface. Some plates are incubated at 37Â° C in a 5% CO 2 atmosphere: the temperature and conditions at which some of the body's bacteria will grow.Special incubators can maintain these conditions.ungi, and some bacteria (e.g. Yersinia sp.), should be incubated slightly cooler. This is usually 30 Â°C, and room air often is used. Yoghurt bacteria grow at much higher temperatures (typically ~45 Â°C). They are therefore particulally safe to use when teaching microbiology, especially to children.