Question
I am a carnivorous plant collector but I also collect orchids. I have this one 'lime green' phalaeonopsis orchid that will not grow property. I also have a healthy one that will not bloom. Here are my conditions:
South windowsill: natural light: 5-6 hrs a day
watering: once a week
fertilizer: once a week: quarter strength
I have attached a picture of the unhealthy  but the healthy one has medium green leaves that are stiff and thick. Could you please help?
thanks!

Answer
Thanks for the picture Zack.  It appears that the size of the fir bark is too large.  Fir bark is difficult to wet as, when dry, it is hydrophobic.  That is why in commercially prepared orchid mixes, wetting agents, such as perlite, are added.  The larger the bark pieces, also, the more difficult to keep it wet.  The fir bark should have been soaked for an our or more prior to use.  When watering,  soak the potting mix thoroughly.  If you had used smaller size fir bark and/or a mix with perlite, once per week watering would work well,but, with the particle size you use, you will need to increase watering frequency, and/or soak the mix more thoroughly.

With regard to flowering, try placing the plant on an east window sill.  Phalaenopsis prefer the morning sun. A south exposure results in lower light levels in the spring and summer when direct sunlight comes from a more northerly direction.  Most phalaenopsis flower in late winter/ early spring.  A southerly exposure also provides too much heat and light in the winter when the sunlight comes directly from the south.