Light pollution is a growing problem. An increasing body of evidence proves that light at night has deleterious effects on flora, fauna,
and human health. It’s time to re-evaluate our night lighting around our homes and in the garden. Among the findings:
Continuous lighting depresses the formation and maintenance of chlorophyll in leaves and promotes lengthening of the
internodes of the branches and expansion of the leaf area.
Light falling on pond water increases algae growth.
24-hour lighting inhibits flowering and promotes vegetative growth of short-day plants; encourages continued vegetative
growth and early flowering of long-day plants; and increases stem lengths of day-neutral plants.
Excessive exposure to artificial night lighting can alter basic biological circadian rhythms, change predator-prey relationships,
and even trigger deadly hormonal imbalances.
Researchers found that artificial night lighting disrupts the physiology and behavior of all nocturnal animals studied (half the
species on earth are nocturnal), including birds, bats, frogs, salamanders, fish and fireflies.
Bats, which are good for insect eating and therefore a positive addition to the garden, are less likely to cross a barrier of
Illuminated buildings confuse migrating birds accustomed to navigating by the stars. Some smash into windows and others
drop from exhaustion after hovering moth-like around the lights. With estimated deaths at more than 100 million a year, major
skyscrapers in Chicago and New York have begun dimming their lights.
Winter dieback can be severe on lighted trees during the following spring because dormancy was delayed.
The beauty of a natural nocturnal environment and a star filled night sky are both increasingly rare sights in our developed world. The
night is beautiful in itself as is our landscape when lighted by a full moon and by star light, for those lucky few with a very dark
The recommendations to protect the health of our gardens and our nocturnal environment are simple:
Use the lowest amount of light necessary to see foliage (usually in the range of 7-20 watts incandescent).
Highlight the garden sparingly and with shielded light bulbs.
Turn off the lights when you are not there and in the middle of the night.
NOTE: Many efforts are underway to limit “light pollution” including by the US Fish and Wildlife, the National Parks system and an
increasing number of municipalities, in order to control “light trespass”. The Garden Club of East Hampton supports all local
initiatives to reduce excessive landscape lighting.
Go to: www.darksky.org for more information on light pollution and for a selection of “dark sky friendly” light fixtures.