Question
My orchid plant has grown two new spikes with a lot of buds, but the buds are drying out and not opening, I have had orchids now for over twelve months and not had this problem before. I water once weekly.where am I going wrong.

Answer
Grace, I'm going to assume that you bought this plant in flower a year ago and it is now trying to rebloom again. I'm also going to assume that you have not repotted this plant since you brought it home.  It is recommended that phalaenopsis orchid plants be repotted in a special orchid potting mix after each flowering.  If they are not, the potting mix is decomposed to the extent that it is soil-like.  In this condition, it retains too much moisture and restricts air flow to the roots.  Unlike most other plants, in nature, most tropical orchid grow with their roots exposed to air, so the environment in the pot requires a special potting mix and frequent repotting to maintain that environment.  It also helps to grow them in a pot that has lots of drainage holes.  When the potting mix deteriorates, roots tend to rot restricting the flow of nutrients  to the leaves and floral parts.  Best time to repot is after flowering.  In the meantime, ease up on the watering to reduce any further root loss prior to repotting,  Dead roots are mushy, so, when you get to unpotting the plant preparatory to repotting, you will be able to see the extent of root damage.  Be sure to remove mushy, rotted roots prior to repotting.

Other factors which interfere with bud opening include low humidity and temperatures below 70 degrees F. and low light.  If your leaves are a dark green, that suggests insufficient light for the plant to complete its flowering cycle.