Nah. I still don't wanna argue (but I guess I will -- a bit).
There may be 30 seconds some time in the course of a year when
conditions around ONE of my trees match the specs set out by MSU.
Dang! I wish I could figure out which tree it was.
The University of Florida has this to say:
"Foliar applications. In general, foliar applications of N, P, or
K have not been shown to be effective where a good soil fertility
program is followed. It is difficult to place enough of these
nutrients on the leaves, especially early in the growth cycle, to
be of benefit. Foliar applications of micronutrients can be
effective in correcting micronutrient deficiencies (Table 5 ).
Nutrients such as Ca and B, which are immobile in the plant,
should be applied in small amounts at high frequency rather than
in one application for correcting temporary deficiencies in some
leafy vegetables. . . ."
In another article, UF notes that foliar application of NPK to
leaves is useless, but says that iron deficiencies may be
corrected either by adding S to the soil or by frequent foliar
application of a weak Fe solution to the leaves.
So . . . In summary, for field-grown plants . . . Foliar feeding:
Maybe for a few micronutrient problems, IF you know which
micronutrient is causing the problem. Don't bother for general
feeding of the plant.
In bonsai (which was the subject of NONE of these studies (above
or below)) an every-two-week regime of regular fertilization with
a balanced fertilizer that contains the necessary micronutrients -- and we all do at least that, don't we? -- will
make foliar fertilization, especially as described below, a waste
of money, time and effort (and fertilizer).
But since it is unlikely to do any damage, if you want to do it .
.. . have at it. I'll be resting in the shade drinking a Sam
Adams ale.
Jim Lewis -
jklewis@nettally.com - Tallahassee, FL - Bonsaiests are like genealogists: We know our roots!