Arrggh! The first plant to bloom on my first living wall, and it's a terminal spike! I'm surprised it's sending up a spike at all - the root system hasn't established very well yet. I mounted it last June, and it had an old spike on it at the time. It has sent up two leaves since then, and now this.
So what are the chances that it will send up a basal keiki? How do phals with terminal spikes generally fare?
Your plant will still survive and maybe a basal keiki will appear or form some keikis from the spike but the mother plant will no longer produce new leaves. The slow death is yellowing and falling of old leaves but it will happen for a long time. I have a Phalaenopsis that have a terminal spike and it gave me three basal keikis but it is still alive after a couple of years.
It may still even bloom from lower, previously unbloomed leaf axils.
One of my Phals got a terminal spike last year (had a normal spike, as well, at the time) - it's since started a basal growth (actually growing just below the parent's crown), and now has a new spike coming along.