The odd one out!

Easy to spot...the little one in the front doesn't want to grow; I gave it to my friend last year it fine not a large orchid but I had hopes.
Sadly it has not so far full-filled my hopes for it, she has asked me what is she doing wrong?
The flower on the right is this years from Asda the other two are from last year...from Tesco's I also have another huge purple orchid from last year which has spread itself along the window ledge.
Neither my upstairs friend or self can work out why the little one remains rather small.
It looks healthy enough I'm not sure about the stuff its been grown in; the others are all in a bracken type of 'stuff'.
So I wait with trepidation to see whether it will even flower now.

Not a particularly nice day here in Liverpool hope yours is much better.