There is encyclopaedic information on artificial lighting of plants even on
the net. I still write this because questions about the different spectral
light intensities, day/night periodicities & other growing conditions for
different species & varieties seem in need of constant appraisal.
To provide plants artificially with the balance of red & blue light they are
purported to need a ratio of one fifth less efficient tungsten & four fifths
more efficient
fluorescent lighting has been recommended . Apparently for "normal" plants
blue dominant red deficient light causes petioles & stems to elongate so
leaves can then more quickly reach more light. But for shade plants do
they need red light less & for some e.g. the most delicate Ferns do they
need any at all? It is interesting to see the astonishing growth rate &
flowering of Spathiphyllum & other "shade" plants very close to fluorescent
& other lighting which has little red.....When I first experimented with
shade loving tropical terrestrial & aquatic plants relatively low efficiency
chokeless mercury lamps deficient in red light usually produced plants of
fine form & colour. High efficiency red rich Sodium lighting at 3 watts per
square foot (500-1000 lumens) bleached/"burned" Spathiphyllum. So I wonder
how important red light is for shade loving species like many
Spathiphyllum?. I abandoned red rich tungsten lighting in favour of at
least partial fluorescent long ago. Currently the latter seems by far the
cheapest in bangs per buck in capital & running costs. Spathiphyllum (&
other shade plants) grow & flower well nder "warm" tubes, continuously lit
at intensity of even 2 watts (only 100-200 lumens per square foot. With
artificial lighting designs becoming more & more energy efficient &
spectrally appropriate tropical shade plants can now be grown economically,
superbly, in the coldest & least sunny of regions without un-natural winter
break in insulated "boxes" in which conditions can be "controlled", plants
safe from external perils.
So...is fluorescent lighting (alone) adequate for growing plants. For me
for some shade plants the answer is "Yes". If I lived in an equitable &
stenothermal tropical/sub tropical region free of environmental, social &
other problems, there would be little or no need for big protective boxes
with artificial lighting. BTW all this is academic. The World
Spathiphyllum Collection is in a huge "cold" frame in the house yard
unheated & illuminated now only by very filtered natural light. I am
unable to take them through yet another winter here or fit & rich enough to
keep them so they are on Death Row.
Ron Iles
----- Original Message -----
To:
Sent: Monday, August 16, 2004 11:08 PM
Subject: Re: [aroid-l] overwintering alocasias
> Leslie,
>
> All this sounds good. But does fluorescent light cover all the spectrum
> needed by plants? I don't know anything about this, so I guess it's a
> question to everybody else. > Philippe
>
>
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