In addition to the vendors already listed, I have always had good success buying orchids from
www.seattleorchids.com and wwww.botanicaltd.com. Although I've never had the opportunity to purchase from
calorchids.com, I've read many times they sell very nice, healthy orchids as does Maui Orchids in Hawaii.
I'd also like to add my two cents about ordering older, mature orchids from some of the larger vendors in the USA & Hawaii.
When I first started growing orchids in my home approx. 5 yrs ago, I had a lot of difficulty with fusarium wilt infecting my plants. I thought it was my own cultural practices and I really buckled down to make sure I was following all of the recommendations to prevent disease in my growing area.
It took a long time for me to finally realize that one of the vendors I had been purchasing from was selling diseased plants. When I began to suspect the vendor, I actually contacted another vendor to discuss this problem and how often it occurs. This vendor (I don't want to identify anyone) advised me that they spray their greenhouses weekly to control diseases such as fusarium. If you are unfamilar with fusarium wilt, it is a devastating disease which is contagious and can be controlled but not eliminated by a spraying program.
I realized looking back that, when I received these orchids from the suspected vendor, they were large plants and initially appeared very healthy only to begin a slow and steady decline. When I cut off parts of an orchid that eventually developed a visible diseased area, I would find that pink ring around the pseudobulb and darkened tissue which confirmed it was fusarium I was dealing with.
Now,this is my opinion and my opinion only, but I believe the longer an orchid is sitting in a vendor's greenhouse who is not practicing sound cultural practices, the more opportunity there is for it to become infected with a disease since most disease is spread by watering and plants sitting too close to each other.
These vendors have costly spray programs where chemicals are applied routinely to control diseases in their orchids. It is my feeling that, if you do not have a similar spraying program in effect, the disease will eventually manifest itself and you may not be able to control or eradicate it at that point.
Once I no longer purchased orchids from the suspected vendor, stopped purchasing orchids from large vendors which were listed as being more than a year or two old and stayed on top of my cultural practices, I became much more successful in preventing disease in my collection. I still have an occassional problem but not from any particular vendor.
I'm sorry to go on for so long but I came very close to giving up orchid growing as a hobby because of this situation. There are good vendors out there and some have very large greenhouses and nice healthy plants. I would suggest you follow the recommendations of the other orchidboard members for vendors and, as someone else, mentioned, check Dave's Garden for additional opinions on vendors.
I also agree that purchasing orchid seedlings is risky unless you are an experienced grower. Seedlings are very vulnerable and may not acclimate easily to your growing conditions.
Any feedback, negative or positive, is welcome to my opinions. Good Luck & Happy Growing.