I am not a fan of the slow-release fertilizers in the first place, as you
really do not have as precise the control over the feeding rate as one might
think. Nancy is right about issues in S/H culture, and I will add that
those prills can clog the air flow to the root system. (By the way, lest
you
get the wrong impression, roots growing into the S/H pot reservoir are no
issue.)

I have heard of folks putting the prills in an old stocking which is placed
on the medium surface or hung above the plant so the rain washes the
nutrients into it, but again, you really have no control.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Artwork, Books and Lots of Free Info!


"Nancy G." wrote in message
oups.com...
jtill wrote:
This has not been discussed in a year or so. Some approved it some were
doubtful in past postings. Any new opinions? My orchids are outside
here near Houston on the gulf coast and it has been raining for weeks,
heavy, long rains. My orchids love it and are growing wildly (for
orchids). Seems it would be good to have a constant supply of food for
them. My present problem is that I would have to feed daily as it is
flushed out quickly in this rain! I am exclusive with S/H, is that a
problem? Do the used prills pose a problem? Should they be removed?
Joe T
Baytown (the ol' swimming hole) Tx

From personal experience, to be administered with a grain of salt.

In S/H I don't recommend time release unless suspended above the mix.
If you feed as normal, the fertilizer will accumulate a small amount as
sediment in the pot and not be washed out by the rain. The roots will
go to the food. It is probably better to be a little light on the
salts with S/H to avoid build up when the rain stops and you get on a
normal watering schedule or you want the plants to rest.

For orchids in bark or CHC. Yes you can use time release. It is
probably best to use the bead (osmocote or miracle grow) style in a
mesh bag suspended above the pot. If you try sprinkling it directly on
the mix it can leave "hot" spots that may cause problems during the
winter when the watering schedule is reduced.

I have mixed time release systemic in the mix of my larger semi
terrestrials and terrestrials(usually Cyms and Phaius) for the summer.
If it is fresh mix I use about 1 TBS per gallon of medium and blend
it in while mixing. If adding it to the top of the pot, I reduce the
amount to about 1/8 tsp per quart (4" pot = 12 square inches) 1/4 tsp
per 6" pot (18 sq. inches). Don't add more than that or too late in
the season or you may have too much accumulated to dissolve and be
inert by the end of the growing season. Check the packaging to see how
long it will feed or the frequency to reapply.

I also take my orchids outside during the summer. This year when the
phals were drying out too quickly after being watered, I added some
(gasp) miracle grow potting mix as a top dressing. It was
pre-moistened and maybe 1/2" or less added to the pot (it was about 1
cup per 6" pot, spread evenly around the top of the mix). The phals
had all been freshly potted into bark and needed a little more moisture
retention. They've taken to it really well, plus I've captured rain
water and use it on my orchids.

There was one grower that told me, he doesn't feed his orchids if it is
raining. The atmosphere is 70% nitrogen, and for some reason a rain
drop captures it and the plant can use it more efficiently than pouring
a bucket of water over the roots. True? Beats the heck out of me, but
I do know that one good rain will do the orchids more good than all the
water I can pour or spray on them. Maybe it's the microdust in rain...

Best wishes,

N.