Yug

As the other's said, the inflorescence is dead, snip it off close to the base. They don't last forever.

If I may comment on an earlier post - you can buy either sphagnum moss, or peat moss (dead high-acid half decomposed plant matter), not sphagnum peat moss. For orchids, spahgnum moss.

As orchids go, most don't like a mix that retains too much moisture. Root rot from overwatering is how most 'newbys' kill orchids. That being said, phalaenopsis, as a rule, prefer more moisture than most other orchids. BUT, do not leave any water in the crown overnight. This can start crown rot, and could cause you to lose the entire plant, since the crown is usually the only growing point for phals (and vandas), and unless it is a large phal, it may not be able to live long enough to put out a side shoot and recommence growing. I am fanatic enough about my phals that if I see water in the crown after 5pm (better to water in the morning, and avoid probs), I have taken a drinking straw and blown air in the top to blast the water out of the crown.

That dried stem, when still green is usable. Once it dries up, though, it doesn't do anything except detract from the plant's appearance. After the initial blooming, when the blooms begin to drop off, you can stimulate a 2nd blooming by cutting just below the lowest bloom (unless you have pendulous blooms like I grow mine, then you cut just above the highest bloom - I like the more natural cascade effect rather than staking it vertically). Once an 'eye' has become a branch, bloom, or keiki it will never be able to used again; if still dormant, it can become any of those three or it can stay As a rule if you want a 2nd blooming, give more light; and if you want keiki's give less light. A dab of keiki paste under the small calyx covering the dormant 'eyes' helps, too. A word of caution. Don't try for a third blooming; it takes a lot of energy for the plant to bloom, and after a 2nd blooming it needs a rest, otherwise you are weakening your plant, and this leaves it more vulnerable to diseases and pests. Some large older phal can put up 2, 3 or more inflorescences without any problem, but I wouldn't allow that with a young plant. I had a Phal. aphrodite that had 4 spikes and was at the same time growing 2 side shoots from the base. Three of the spikes grew blooms, and the other parts stayed dormant until it finished blooming. Then the side shoots started getting larger, and the smaller spike started making more flower buds. I guess it was parsing its energy out over time, but most phals would have just exhausted themselves by developing everything at once.

As far as the potting mix goes, usually the small seedlings are in sphagnum moss. It retains moisture, and is easier for the vendor to pot with. As the plant gets larger though, it packs too tight, and prevents good gas exchange around the roots. These generally grow on the side of a tree, and the roots have constant air exposure. The part attached to the bark gets the moisture, not the whole root, and if you have constantly damp tightly packed sphagnum choking the roots, you will eventually get root rot, and a dead plant. My larger phals get a bark/moss mix or just straight bark depending how much moisture I wish to keep in the pot - more moss = more moisture. Not everyone has the same growing conditions (and these will vary throughout the year) so you have to try different mix combinations, then feel and observe your plants, and adjust accordingly. I can give you general rules for a specific type or orchid, but you may still need to alter them for your specific locale/conditions. It ain't a 'cookie-cutter' solution that works equally for all of that particular type of plant.

Whew! That was a mouthful. Hope this was helpful.