Hi, I am new, and I don't know how much you know about orchids, so if I tell you something you already know, please excuse me. I am just being thorough.
They reccommend that because the bacteria that break down the bark use up a lot of nitrogen. For me, I use any of the orchid fertilizers so long as they don't have nitrogen derived from urea. Urea N takes a while to break down, so it doesn't get used by the orchids because it rinses out of the medium when you water. So, make sure to use a special orchid fertilizer-I use gubler personally. I also have schultz and wonderlizer, but they both have urea nitrogen, so I stopped using them for my orchids. I didn't know this bit of info about the urea until recently. Use a high nitrogen fertilizer, usually 1/4 strength every week, or every second or third watering. I don't know if you have heard the expression, "weakly, weekly" but it is a good rule to follow. Then, about a month or two before it is time for my orchids to bloom, I start using a high P and K fertilizer. It has a low number at the start, and then a high either middle or last number. Can't remember which. Lately, I have been using "spoonit bloomit" fert. from fred myer. It is 6-30-30. I can't say if it works great yet, but it hasn't hurt my plants, so that is always good. I decided to try something new, because I ran out of my schultz flowering fertilizer.
Also, I have heard amazing things about a product called worm tea. I bought some worm poop to make my own, but I don't know if it will work as well as the stuff I have seen online. If you want to know more, there is info about it on orchidgeeks.com in some of the threads. You can do a search for it on there, and it should be easy to find. Anyway, I am sure there are people here who know way more than I do about fertilizers, so just take what I say with a grain of salt.