In most cases, the microorganisms are not growing due to the temperature in the incubation environment being too low. All cultures used in the lesson will grow at ambient temperatures between 21 ^oC and 25 ^oC (70 ^oF and 78 ^oF) within approximately 1 to 3 days of inoculation. Incubation temperatures lower than 20 ^oC (68 ^oF) will significantly increase the amount of time required for culture growth.