Regarding Osmocote and aquatic plant fertilization:
When I first tried growing water lilies, the reference books all made
suggestions such as: "These plants need good, heavy loam, or clay soil
enriched with one sixth of its bulk of decayed cow manure..."
(Reader's Digest Complete Book of The Garden, 1966), and " For
soil, fill the boxes three parts good garden loam mixed with one part
well rotted cow manure, plenty of bone meal and some blood meal is
best..." (The Complete Book of Garden Magic, M. E. Biles, 1956).
While some would applaud the old "Green/organic" procedure, can
you say GREEN WATER?
The advent of hybrid water lilies and their need for higher levels
of nutrients to support their high rates of blooming led to the use of
regular fertilizer to support this need. In order to provide such a
high level of nutrients and also keep the nutrient load out of the water
column, the procedure of encasing the fertilizer in a ball of clay was
developed. It was discovered that the nutrients would actually bind
with the clay molecules, keeping them out of the water column and
still be available to the plant. But to keep the ferilizer below the
"burn" level, it was necessary to fertilize the plant often. To avoid
having to pull the pots from the ponds several times a year to add
fertilizer, the use of pond tabs came into vogue. Using a probe, the
tab could be inserted into a pot without removing it from the water.
Nutrients in the water column would still result, however. Using time
release fertilizer allows one to add enough nutrients to last the entire
growing season when repotting is done in the early spring. Packing
clay around the fertilizer and placing it in the bottom of the pot keeps
the nutirients available to the plant and out of the water column as
noted above.
Now as far as I can tell, I was the first to mention using Osmocote in
water lilies and lotus on Garden Web back in 1999, and additionally,
the process may even have originated with me, as when I began using
it I had not heard of anyone else doing so. So if you want to blame
someone for plugging the product, I'm your man. Because Osmocote
was the first widely available time release fertilizer to come on the
market back in the early 1970's and because it was the only one for
years, the term became pretty much synonymous with "time release".
It was not until the early 1980's that the product began to be sold to
consumers, rather than just commercial producers and that is when I
was first able to purchase it in plain paper bags filled from a
greenhouse's 50 pound bag by a very helpful employee. Multicote, by
Haifa, was not on the market until the 1990's.
For the most part, if someone went to their garden store and asked
for "time release fertilizer" they were apt to be looked at funny, but if
they asked for Osmocote, the clerk knew immediately what was being
asked for. Anytime I use the term "Osmocote" it is not to advertise a
particular company, just as in the vernacular If you say "Google
something" you are really saying "Use whatever search engine you
like, but look it up on the Web".
Now for a reprint of a post I made to IWGS nine years ago in August
of 2001:
"There may be some confusion about the action of timed-release
fertilizers as they apply to feeding water lilies over the summer
growing season.
Allow me to elucidate:
I use a timed-release fertilizer known as "Multicote 6", manufactured
by Tri Pro Inc. It is labeled as 15-15-15, but includes 1% Magnesium
and .15% iron. It is a polymer coated NPK fertilizer programmed to
release nutrients continuously at a rate adjusted to plant
requirements. The release rate is governed by temperature.
Multicote 6 releases nutrients evenly over 6 months at 70 degrees.
The release rate is affected only by temperature, not by moisture, nor
by bacterial action. Below are the release rates for various average
temperatures:
Average Temperature Longevity
60 7-8 months
70 6 months
80 4-5 months
90 3-4 months
One can easily see that in a climate such as zone 7a in which I reside,
that even if the pond water temperature was at an average of 90
degrees for 3-4 months, that the timed release fertilizer would last at
least that long. In other words, assuming that water average
temperature was 90 degrees all summer long and you fertilize with
this product on May 1st, it would be actively releasing nutrients
continuously THROUGH at least mid-August. Not bad, even at the
worst case. Actually, my pond water NEVER approaches 90 degrees,
or even above 80 degrees, and the average temperature from April 1st
(when I do most of my repotting) through September is closer to 70
degrees, giving me nutrient release all the way from may 1st to
September 30. Not only that, but the release increases as
temperature rises, and decreases as temperature falls, matching the
water lilies demand for nutrients, as they grow faster at warmer
temperatures and slower as temperatures drop.
In my never so humble opinion, this beats the nada out of pulling a
hundred or so pots out of the pond every month to shove in a tab or
chunk of tree spike."
