Juniper and Ficus Bonsai - Canadian Winters

Hello!

I have a couple questions for you experts:

1) Should I leave my Juniper bonsai outside for the winter?
2) I'd like to pluck some Maple Tree seeds off the ground/from a tree and grow a bonsai from seed. I looked over the guide, but I'm wondering if that too should be left outside during the winter, as it would be in nature.

Thank you!

Juniper outside yes of course they re a totally hardy species. Seeds of Maples, also yes. sow as soon as you can and leave outside they will germinate when they are ready in spring