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.
Lift one edge of the plate cover while the plate rests on the bench. Place the inoculum on the agar at the top of the plate. Use close, parallel strokes to cross back and forth over 1/4th -1/3rd of the plate (a). Close the plate, turn the plate 1/4 turn counterclockwise and sterilize the loop.