In order to grow organisms, you need to provide an adequate environment suitable for their growth.
Things to consider are (but not limited to):
- Temperature. Does it grow best at room temperature or in an incubator?
- Aerobic, anaerobic, and everything inbetween.
- Acidity.
- Room to grow. You need to provide enough space for your organism to grow.
- Nutrients.
Consider your culture medium—basic building block nutrients for your organism to grow.
A broth medium is a liquid nutrient environment. It is good for growing a large number of organisms in a limited volume (generally a test tube size). A loop is usually sufficient to inoculate the broth. Visually (naked eye) examine the sterile broth. Note it’s opacity and viscosity. After inoculation (and after adequate growth time), note the broth’s opacity. You should be able to notice a difference—usually a “clouded” effect; particulates; maybe color change at the surface or bottom of a tube; and opacity.
An agar medium is a semisolid (.ess than 1% agar) to solid medium (1.5-1.8% agar) suitable for a slant test tube, deep test tube, or plate. Agar comes from seaweed and contains galactose (no real nutritional value). One can mix in different nutrients (whatever you need for a task) into the agar base. Agar is liquid at 100 °C and solidifies at 40 °C.
Reference
Cappuccino, J. G., & Welsh, C. (2018). Microbiology: A laboratory manual.
