I am trying to start some olives from cuttings. I have had them in perlite in a container with a bag over the top and rubber band holding in the humidity for the past 2 weeks. I noticed today that there has been mold starting to just form. I removed some of the moldy looking areas, just debris at the surface of the perlite, and gave them a good watering.

Are they doomed, and why does this happen?

Do I need to let some fresh air in every so often?

Thanks in advance.

Remy