"Ray" wrote in message
...
My opinion: use them whenever you want, but in different concentrations,
based upon the amount of nitrogen you want to apply. As you didn't
include
the actual makeup of those nutrients or the trace elements, I really
didn't
have the options of "always" or "never."

Basically, all the three formulae contain all the basic trace elements as
claimed by the manufacturers. I feed my orchids weekly, always half strength
of the recommended dosage. As most of my plants are now approaching their
"puberty" stage (so to speak), I am begining to switch from the N21 P21 K21
to N13 P27 K27, to prepare (majority of) them for blooming towards the
second half of the year. Of course I do drenching every other week.

The reason I enquire is that prior to this, I have a few phals. and cats.
which grow and bloom beautifully only on organic feed applied every
tri-monthly but the downside is pest control. Enlighten me further, please!
BTW, I am living in Malaysia, a tropical country with an excellent humidity.

Thank you.