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.
Use agar and petri dishes to grow bacteria cultures. Nutrient agar works well for general use. To make an agar plate, just heat the agar and pour it into a sterile petri dish.Rub a swab along a surface you want to test (your mouth, the bathroom counter, etc.) and then smear it in a zig-zag pattern on the surface of the agar plate.Getting started:o make an agar plate, just heat the agar and pour it into a sterile petri dish. Rub a swab along a surface you want to test (your mouth, the bathroom counter, etc.) and then smear it in a zig-zag pattern on the surface of the agar plate. Getting started: