How to make this flower printable?

flower - celeste.skp (232.1 KB)
Is it possible to add depth to the petals of this flower to make it printable as STL?

Yes. Use the oFfset tool and PushPull tools.

For example, using a 3mm offset and PushPull distance, and a displacement of 3mm, I created this:

flower - celeste.skp (232.1 KB)

Is that what you had in mind?