Yup, the big green/white bag of Greensmix Sphagnum Peat Moss or Premier Sphagnum Peat Moss is all you need. The Premier bag looks like this:
Get rid of that Miracle Grow asap. I had a guy buy a $100+ Nep hamata cutting from me and plant it in Miracle Grow, which of course killed it within a few months. Then he wanted me to send him another cutting or a refund. All I did give him was chastisement however since I had a website which told him how to grow it and I'd even sent the cutting rooted and potted all he HAD to do upon receipt was give it the right conditions...
Anyway, go buy some Sphagnum Peat Moss today. You'll have to look way out back by the big bags of mulch and stuff NOT by the small bags of houseplant supplies. My bag was 2.2 CU Ft and it ran me a whole $3.00 but it may only last me 5 years considering I don't like using peat very often, I like using Long Fibered Sphagnum Moss (or "Orchid Moss" at Lowes) for most of my CPs. If you don't wanna buy the Greensmix bale and have to store it til needed later then just buy the orchid moss which is by the houseplant supplies. It's a brick that looks like this:
Orchid Moss runs about $5 a brick and I believe the small brick is enough for six or eight 4" pots.
Incase no one has told you yet, make sure you only water your CPs with Rainwater, Reverse Osmosis or Distilled water. Tap water or well water is generally not pure enough for these plants and will kill them just as fast as incorrect soil.