Make 5× M9 salts:
| 64 g | Sodium phosphate (dibasic, 7 hydrate) Na2HPO4•H2O |
| 15 g | Potassium phosphate (monobasic) KH2PO4 |
| 2.5 g | Sodium chloride, NaCl |
| 5 g | Ammonium chloride NH4Cl |
Combine the following ingredients (all pre-sterilized):
| 200 ml | 5× M9 salts |
| 2 ml | 1M Magnesium sulfate MgSO4 |
| 0.1 ml | 1 M Calcium chloride CaCl2 |
| 40 ml | 10% (w/v) glucose (or other carbon source) |
To make M9 plates add the items above to 16g of sterilized agar.
If making less than 1 liter use 8g of agar per 500ml of solution.