With the verticillium project going on, we’re using tons of petri plates and slants. These plates and slants are filled with mediums that have different levels of selectivity- the more selective medium prevents less things from growing on it than does a less selective medium.
The mediums are made out of a variety of different ingredients. They’re gel-like in substance and contain agar, which is kind of like a gelatin that comes from algae.
This day, we needed to make some more slants and plates. All of the recipes are in this handy dandy book.
The slants we made had CPA or Czapek-Dox Agar. This recipe was just for the broth, but we added agar.
And the plates we made were 1% Potato Dextrose Agar.
First I made the PDA. This recipe is pretty simple and only has a couple ingredients. First is water!
500 mL makes quite a few small sized plates.
Next is the potato dextrose and agar. The potato dextrose smells a little bit like instant mashed potatoes!
In they go…
And then the same general instructions follow for the CPA.
For the slants, we fill them about 1/3 of the way full. We don’t pour the plates yet.
After pouring the slants, we autoclave both them and the un-poured plate medium. The autoclave is like a huge pressure cooker and sterilizes anything that goes into it.
After the autoclave, we tip the slants sideways so that they melted medium gels tilted. 
The plates are made by simply pouring the medium into the empty petri dishes and left to cool. We do this under the hood, which helps to keep everything sterile.
From here, we have lots of nice, sterile plates and slants we can use for future use!
