Question
i have a phalaenopsis orchid that has been blooming for the past two years and doing great.  recently it has stopped blooming and the stalks are now brown and withered.  i can not cut it back to re-bud because there are no more green stalks with the healthy buds. what can i do to keep my beloved plant alive? please help!!!

Answer
Annie, you are fortnate that your plant has finally stopped blooming. Like all of us a plant has just so much energy to expend.  If it expends too much on producing flowers, it has less to build new healthy tissue.  The second point is that phalaenopsis need to be repotted following blooming.  These are not your standard houseplants.  In the tropics, where they originate, the roots are usually exposed to the air.  Potting mix tends to break down over time and becomes more soil=like.  This retains to much moisture and reduces the flow of air to the roots.

You need to locate a bag of orchid potting mix.  This will have fir bark chips, charcoal and other somewhat chunky ingredients (Lowes and Home Depor Garden centers carry this as do many other garden centers). Take a portion of the new, fresh potting mix and soak it while unpoting your plant.  Rinse the old potting mix from the roots and remove any roots that are collapsed or mushy.  Healthy orchid roots are firm and turn green when wet.  You should repeat this process each yesr following flowering.  I recommend you repot to a plastic pot with lots of drainage holes in the bottom and/or sides.  This will help improve drainage and air movement at the root level. Complete the repotting by placing the root mass into the plastic pot and slowly add the wet new potting mix-- do this in an area where excess water can drain out.  Tap the pot as you add potting mix to help distribute it amongst the roots.  When finished place the plant where you have had success growing it or in an east window.

Phalaenopsis orchids normally send out new flower spikes in the spring.  This is in addition to any flowering that might occur from old flower spikes.  This is why you shouldn't be concerned that an old flower spike turns brown and dies.  Your plant needs a rest and time to grow new roots and leaves.  This respite from flowering is a good thing and provides you with an opportunity to improve the growing conditions for a future flowering in 4-6 months.  You may cut off the old brown flower spikes as they will not rebloom.