NGM plates

Per Liter of medium (~75 plates):

  • 975 mL Water
  • 3 g NaCl
  • 2.5 g Peptone (Fisher BP1420-500 $78.80)
  • 17 g Bactoagar

This is what I did by mistake: per 1.5 L (112 plates):

  • 1462 mL Water
  • 18 g NaCl
  • 15 g Peptone (Fisher BP1420-500 $78.80)
  • 25.5 g Bactoagar (haven't added it yet)

So I labeled it NGM 4X.

I made 4 liters by diluting 975 mL 4xNGM with 975 x 3 mL water, then added 68 g bactoagar.

Stir flask to distribute ingredients.

Autoclave with stir bar inside

Cool to 55C in a 55C water bath

Add per L (see recipes in stock solutions):

  • 1 mL cholesterol (5 mg/mL in 95% EtOH)
  • 1 mL CaCl2 (1 M, STERILE)
  • 1 mL MgSO4 (1 M, STERILE)
  • 25 mL K-phosphate buffer (1M, pH 6.0, STERILE1)

Swirl flask to mix

Dispense 10 mL into each 60mm dish.

Stack 10 high

Let stand for ~48 hours for condensation to evaporate

Pack in sterilized plastic boxes.


  1. 3.3 mL K2HPO4 + 21.7 mL KH2PO4