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.
1 Inoculate TSI Agar by first stabbing through the center of the medium to the bottom of the tube and then streaking on the surface of the agar slant.  Leave the cap on loosely and incubate the tube at 35Â°C in ambient air for 18 to 24 hours.