Date: Wed, 02 Dec 1998 11:02:33 -0500 From: Perry Malouf <pmalouf@access.digex.net> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3790$foo@default> Subject: Ruminations on fertilizing Nepenthes
I have some observations to report which may be
due to the application of foliar fertilizer to
my Nepenthes. First I will describe the apparent
effect on the plants, then I will describe the
way in which the fertilizer is applied. Finally I
will ruminate on the possible cause-and-effect,
and a remedy.
The obvious effects were observed in several plants,
both species and hybrids. These effects include:
1) new leaves which are a factor
of 1.5 larger than those which grew before the
fertilizer regimen, and 2) no new pitcher development.
The new growth looks very healthy, and the leaves do
produce tendrils. But the swellings at the tips of the
tendrils do not develop into pitchers.
There is one hybrid plant which has not shown these
effects, in sharp contrast to the rest. I believe I
have one possible explanation which I present later in
this e-mail.
The fertilizer regimen uses Miracid, diluted to 1/2 the
strength recommended on the box for houseplants (non-constant
feeding). This solution is squirted into the Nepenthes
pitchers every two weeks. All the pitchers on each plant
are treated. The regimen was begun about 7 months ago.
Ruminations:
The cessation of Nepenthes pitcher production due to over
fertilization has been described before, though I haven't
found a specific reference in the scientific literature. I
believe that an excess of nitrogen is causing the observed
effects in the plants.
Most of the affected plants consist of one vine about 40 cm long, with
2-3 pitchers. The one hybrid that has not shown these effects is a
substantially larger plant. It consists of 3 vines, each of which is
1.5 m long. This plant has about 10 pitchers on it, and not all of them
are treated with fertilizer (in contrast to the other plants, which get
fertilizer in each pitcher).
I believe that this large plant is not showing effects of
over fertilization because, essentially, it has not yet
been over fertilized. The ratio of applied fertilizer to
plant mass is much smaller than that ratio for the other
(smaller) plants.
To prevent this from happening in the future, I intend
to not apply fertilizer to _all_ the pitchers of a plant,
especially so for the smaller plants.
For now, I will stop fertilizing for a month or two in
order to allow the plants to use up the nitrogen they've
acquired.
An important aspect of the environment is the high
light level--approximately 1800 footcandles at the location
of the plants due to a halide lamp. In addition, there is
sunlight coming through the windows and hitting many of
the plants. High light levels increase the nitrogen
requirements for healthy, growing plants, and these
light levels are indeed high. Hopefully the plants will
use up the excess nitrogen in a month or so.
And, even more hopefully, normal pitcher production will
resume.
Submitted for the benefit of others, and for the purpose
of discussion,
Regards,
Perry Malouf
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