I have the mega sourdough started used a chocolate mild container from Costco, all plastic.
I drilled two wholes in the top I did use a cup of yogurt and milk
to start it.
if you have heating pad that will stay on. make a tent from a box or hardware cloth they can go under it get warm.
Watch the body language will say who it roo.
We do have the garden in here not watered it much.
The rain has been here.
I made a angle food cake last night, I add cream cheese to most cakes. 10 of our egg whites !