Many don't recommend the Miracle Gro Orchid Mix. And I have heard a lot of bad things about it. It seems to bee too much like dirt and since it usually sits on the shelves a long time and has time to decay even before you get it home!! I've heard that it can cause a lot of root rot! You can order some good stuff online from
rePotme Orchid Supplies - Orchid Mix - Orchid Pots - Orchid Care - Orchid Fertilizer I haven't used them myself as posting to Northern Ireland would triple the price for me..
Or then you could mix some fir bark, perlite, charcoal together and make your own mix. You'll have to see what you can find locally.
What about do you know what kind of orchids you bought? Different orchid species can have a little bit of different requirements.
If not you can just post some pictures and we can id them for you.
Also repotting one that is spikeing might desturb it too much and it might not bloom for you. If the media that it is in is good enough I would leave it until it had bloomed.