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.
Broths are liquid media produced by mixing dry or powder components with water. Agar is a complex carbohydrate, derived from red algaes such as Chondrus (Irish moss) or Gelidium. Agar is supplied in a powdered form and must be melted to mix with water. It melts at 100 oC and solidifies at 40 oC, but will not re-liquefy at room temperature. Most bacteria cannot hydrolyze agar, so when dissolved in broths in concentrations between 0.5% and 1.5% it can serve as a solid base for the culturing of bacteria. A defined (synthetic) medium is one in which the exact chemical composition is known.