Sara. I'm with Al on this one. I think you should put the tree outside right away. If 35 is your lowest temps then you don't have to bury the pot or mulch it or anything. Just set it outside and water when it starts to dry out. Some people do grow junipers indoors rigging up humidifiers, fans, grow lights and leaving the windows open but it's not easy and most of them still eventually die.

Tony