Some types of agar contain added nutrients (such as sheep's blood) which help to promote more vigorous bacterial growth. [substeps] The easiest type of agar to use for this experiment is a nutrient agar which comes in powder form.
[header] How to grow bacteria in a petri dish [title] Prepare the agar. [step] Agar is the jelly-like substance used to culture bacteria. It is made from a type of red algae, which provides an ideal growing surface for many different types of bacteria.