Forget label-recommendations. They vary all over the map and are often off base.
Think of fertilizers like food for yourself: each one has it's own calorie level, so will not be directly interchangeable for each other.
A 5-5-5 fertilizer is nutritionally identical to a 10-10-10, but has half the amount of nutrients in it - i.e., half the "calories".
If you want to get smart about your plant feeding regimen, you need to make some baseline decisions, then be observant and experiment.
The first decision is that of choosing a formula. I used Dyna-Gro "Grow" formula (7-9-5) for years and was quite happy. I later switched to the Greencare Orchid Specials (the so-called "MSU Fertilizers"). There are two formulas of that - 13-3-15-8Ca-2Mg for pure water, and 19-4-23 for water already containing calcium and magnesium. Any fertilizer will work for you, as long as it is complete with trace elements, and not too high in nitrogen (like a 30-10-10).
Second is what feeding frequency will you use? I prefer to feed at every watering, as that probably most-closely matches the availability of nutrients in nature, but every other- or 3 out of four waterings, etc., are perfectly acceptable. I vote against a once-a-month gorging.
Lastly, at what concentration will you feed? That is not an arbitrary decision, as it's like controlling your calorie intake. As each fertilizer gives you a different amount of nutrients, professional growers control their regimen by nitrogen concentration, letting the other ingredients "tag along" in quantities based upon their chosen formula.
Bill Argo, the PhD who formulated the MSU stuff, said that they tried 125 ppm N applied at every watering, and it worked, so that's what they recommend. I used it at that level for about 5 or 6 years and was pleased, but am now experimenting with running at a lower dosage - 75-85 ppm N - to see if there is any impact.
OK, so in my case, I have decided:
- 13-3-15-8Ca-2Mg
- 75 ppm N (+/-)
- Applied at every watering
So to find out how much to mix up, I have to do a little math. 10/%N on the label = teaspoons per gallon for 125 ppm N. 13/%N=ml/L for that level. Therefore, I want 10/13 teaspoons x 75/125 = 0.46, so I'll use 1/2 teaspoon per gallon, or 13/13 x 75/125 = 0.6 ml/L.
If I had chosen a different fertilizer - let's say the Dyna-Gro 7-9-5 - I would use 10/7 x 75/125 = 0.85 tsp/gal or 13/7 x 75/125 = 1.1 ml/L.
If I decided to modify my original regimen to feed every other watering, rather than at every one, I would double my fertilizer concentration, so I'd be giving the plants the same mass of nutrients overall - the same average "calorie" level.
Thank you all for coming to the rescue! 
I, on the other hand, started about 1 year ago, learned quite a bit, but am not qualified to go above the very basic with advise. So I was very happy and relieved when the Cavallery arrived. 
Hey, I just realized that I've started 1 year ago and haven't killed 1 yet. 
Matter of fact, I got my Paph. Pinocchio to spike! 
Linear Mode
