Question
How can I grow cedar trees in my house?
What kind of care do I need to give them?
I pulled them up today, one is 11.5 inches, and the other is 9.5 inches; how long do I have to wait before I can give them fertilizer?

Answer
Yuo don't have to wait at all to fertilize - and hopefully they are still with you since asking this question.  

We harvested cute little seedlings from a private camp in Northern California two years ago, and they are thriving at about 2 feet tall in our Nevada climate (in a protected location) The Calocedrus decurrens are marginal for our area.  They are definitely an OUTDOOR plant, however, as they will get quite large.

http://en.wikipedia.org/wiki/Calocedrus_decurrens

~Marc