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Plant
Nutrition - Know Your Fertilizer
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All
fertilizers are not the same! (For this discussion, the words
fertilizer and nutrients are interchangeable.) Nutritional
elements are divided into two
categories; macro-nutrients, and micro-nutrients. Plants need large
amounts of some elements (the macro-nutrients) and only
trace amounts of others (micro-nutrients). Take a close look and
you'll find some of the major brands are not what they're cracked up to
be when it comes to growing orchids.
What to Look for When Buying Fertilizer for Orchids
1.
N-P-K
Ratio
All fertilizers contain three main elements; Nitrogen(N),
Phosphorus(P), and Potash(K). This is called the NPK ratio. Fertilizer
packages always have three
numbers on the front panel that describes the NPK ratio. The
first number is Nitrogen (N), the second is Phosphorus(P), and the
third is Potash(K).The numbers describe what percentage of each element
is in the fertlizer.
Read
the label:
Look
for 3 numbers on front panel
This
fertilizer
has an NPK of 7-9-5. 7% Nitrogen(N), 9%
Phosphorus(P), and 5% Potassium(K). |
The" NPK ratio" is the ratio of the ingredients inside the
package. Adjusting the balance of these main ingredients between the
growing and blooming cycles is the key to balanced nutrition.
3. Avoid
Eurea
Urea
is an
inexpensive form of nitrogen, the
primary ingredient in all
fertilizers (the first number on the package). Orchids
cannot use urea until it is broken down by
enzymes or bacteria. That's great
for outside plants, but sterilized
potting
mixes don't contain the enzymes needed to
convert urea into something the plant can use.
Unused urea turns to salt and actually becomes harmful to
the plant's root system. This is especially true for
orchids because orchids
simply can't tolerate salt.
Avoid
plant food
that has "urea" on the label!
You might actually be
harming your plants!
The
best source of nitrogen for all potted plants (orchids or houseplants)
is Ammonia cal or
Nitrate. You can find this on the back panel of the package.
Read
the label:
Popular
Orchid
Fertilizer |
Checking
ingredients - Urea is the Nitrogen source! |
This is how
Nitrogen Source should read - no Urea |
2.
Trace
Elements
Plants
need 17
elements for healthy growth. Most fertilizers contain
the three main elements (the NPK - Nitrogen, Phosphorus, and Potash).
But are the rest of the elements there? If your
fertilizer doesn't have all the elements you're taking
a hit-or-miss approach and your plants could be
missing important minerals. Look on
the back of the package and see what's in your fertilizer.
Read
the label:
This is a
very
popular fertilizer -but only 9 elements!. Also, notice
the urea(!) |
This is
Dyna-Gro -
a complete and balanced approach to nutrition. See the difference? |
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How
Can Nutrients with
Lower Numbers Work Better?
It
all has to do with the purity
of the chemicals, not the amount. Many nutrients are made from low
grade
minerals which are much cheaper (1/4 the price!). Low grade minerals
contain filler elements that your plants cannot use - not good for
orchids.
In nature, orchids
cling to rocks and trees. Their roots
are designed to quickly absorb
anything that comes their way. The roots act like a sponge but
are sensitive to harsh chemicals. Their nutrient supply is pure and
doesn't contain
cheap chemical fillers.
Why
jeapordize your plant's health with
cheap fertilizer that's mostly
filler?
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What
About
Organic Fertilizers?
Organic
means
"the nutrient contained in the product is derived solely from the
remains of once living organism". This includes
animal wastes, crop residues, compost and numerous other byproducts of
living
organisms.
Organic fertilizers sound good but most
are incomplete in their nutritional value. They
contain only one or two nutritional
elements so blending different products is necessary.
The result is uncontrollable, difficult to measure, and
usually carries an odor. You never really know what your plants are
getting.
Earthworm
castings, seaweed, and bat guano head the list of
organic remedies. Do you really want to put this stuff on your plants,
and in
your home? Why take a
chance when complete, balanced nutrition is so easy?
Read
the Label:
Here's an
organic
fertilizer I found
at a local garden center. It's
cow
manure(!). |
Look
closer, it's recommended for houseplants? Cow
manure in your living room? |
I
grew up on a farm and my relatives would get a good
laugh at
this one!
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