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Re: too much light?

>Our elderly neighbor has had a street-light installed in her yard.  It is
>nice to have the extra light for security reasons. But since the edge of
>our garden is only 15 or 20 feet from the light, the garden never has a
>time of darkness.  (I mean, I can take a book out into the garden and
>read--I tried it last night.)  I know that onions are sensitive to the
>numbers of light, but is that true of any other garden vegetables?  Being
>a Southern gardener, I normally raise short-day onions--will I now have
>to switch to a long-day variety, or will they even resent the excessive
>light?  I'm just trying to figure out how this is going to affect my
>gardening, if at all.  Thanks for any words of wisdom.



In scientific trials in plant physiology or cultivar quality, the
daylight is sometimes prolonged -- not with huge illumination monsters,
with simple incandescent light bulbs. In other words: with dim light.
This light is too dim to held photosynthesis active, but strong enough
to make plants "think" it's daylight.
>From what you describe I think your neighbor's light is bright enough
to have an effect, especially if you can read a book.
Crucial to decide if the light is really critical is not only the
brightness of it, but also the quality of the light, that means,
the type of the illumination source. To keep things easy, if you
can measure more than 400 lux, this will certainly have an influence
on your plants. The problem is how to measure (you need a good light
meter to do that) and then, what to do: Alternatives are manyfold,
start with nice words, maybe a beer, and try to avoid lawyers.

I am quite sure your onions will suffer. Try it! Plant the same
cultivar in your "illuminated" garden and some in a part that is
not disturbed, but otherwise similar. By the end of June, you
certainly will see if it's worth to shoot the light... (SCNR).
Not only onions are influenced, practically all vegetables have
at least some cultivars sensitive to daylength. Especially sensi-
tive are onions, garlic, leek, chinese cabbage, cauliflower,
endive, spinach, fennel, fava bean, soya, etc., and a lot of
ornamentals.



Andreas


-------------------------------------------------
VIVIANI Comp   CH-8833 Samstagern    Switzerland
E-mail: viviani@active.ch  Dr. Andreas Viviani
Tel: +41 1 786 11 16    Fax: +41 1 786 11 25
Homepage:  /http://www2.active.ch/~viviani
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