Vandas and Fertilizer- newbie question

[Ari]

Now I get that Vandas need a lot of water, light and fertilizer but I'm confused about how to fertilize them. I have Grow More premium orchid food. I have some that says bloom and some that says grow.

Both of my Vandas are in bark. My understanding is that there are no nutrients in bark and so you need to fertilize.

Which fertilizer should I use and how much of it should I use? Grow or bloom?

I guess it says a teaspoon per 10 days but I'm unclear as to whether to use grow food or bloom food. I do want the Vandas to bloom, of course!

At this time Im very good with Phals and pretty good at cats but I have not mastered Vandas just 2 success out of 4 attempts. I think even if you are careful, that it's hard to grow such a tropical plant in Minnesota.