DATE:    10/1/98
WRITER:  Dr. David Bradshaw, Extension horticulturist,
         (864) 656-4949

Row Covers:  Non-Chemical Control
For Insects In Fall, Spring Gardens
 
     Each time I think about starting a fall garden, I anticipate
harvesting large, succulent heads of broccoli and crisp heads of 
snow-white cauliflower. 
     But before I can relish the moment completely, the picture
of a horde of little, white cabbage looper butterflies flits
through my mind. Someday, I think, those seemingly harmless
pollinators will leave little green worms to pester my
vegetables. Needless to say, my anticipation soon turns into
dread. 
     No problem, some would say. Just bring out the insecticide 
and spray away. But if you, like me, are hesitant to use the wide
array of chemicals designed to control insects in your
vegetables, take heart; a row cover may be an acceptable
alternative for you.
     Row covers are available in several forms at most garden 
centers and nurseries. Each provides various forms of protection,
but also has some limitations. 
     For instance, solid film row covers made of polyethylene
must be supported above the crop by wire hoops or a temporary 
framework, and anchored on the sides to prevent them from blowing
off. They also must be monitored closely to prevent excessive
heat buildup.
     Although heat buildup may be a problem in the early fall, it
can be a distinct advantage in late fall and early winter
gardens, extending the growing season well past average frost
dates.  
     Fabricated row covers also can be used in vegetable gardens.
In addition to preventing insect access to vegetable plants, this
type of row cover allows air and water movement through the 
fabric. This prevents the accumulation of excessive temperatures.
Fabricated row covers also are light enough to float freely above
the plants without needing a supporting frame and will lift up as
the plants grow. However, this row cover must be anchored against
the wind.  
     While row covers provide protection against errant late 
frosts that can delay early maturity, that is not their primary 
function. Primarily, I recommend row covers as an alternative to
chemical sprays for insect control. 
     Row covers can protect young, tender plants in early spring 
gardens from first generation insects and moderate late frost.  
But you must experiment with the covers to see which one is best 
for your garden. Each garden site has its own "microclimate," 
which is affected by exposure, slope and temperature. But each
one can be controlled through resourceful experimentation. 
     Sure, it's a challenge to produce high quality vegetables 
without chemicals. But it's that challenge that keeps me
intrigued with the very therapeutic hobby of gardening.
                *********************************
     If you have gardening questions or comments, write to
Agricultural News & Publications, Clemson University, A-101
Poole Agricultural Center, Box 340311, Clemson, S.C.  29634. Our
Web site is http://virtual.clemson.edu/groups/agcomm/."Buds &
Blooms" columns are under "1998 News Releases." 
                             END