I will be putting my mountain bike into a non-climate controlled storage space.
I will be there about 90 days.
Is there anything I can do to minimize rust and corrosion?
Thanks.
As long as there is not much moisture present, 90 days should have no effect on your bike. I've never kept my bikes in climate-controlled storage and never had any problems. But if you are concerned, I suggest washing the bike before storing it (muck and grime can accelerate corrosion), drying it thoroughly, and lubing the chain with quality lube. If you expect huge variations in moisture level, you can also use spray-based rust preventers on the cassette, but apart from that there's not much else.