Georgia vegetable farmers count on plastic-mulched beds to
raise top-quality
produce efficiently. They also count on the plastic to last
more than one growing season.

“Growing vegetables on plastic is not cheap,” said University of Georgia scientist Darbie Granberry. “So
scientists and farmers worked
to learn how to use it for two or three growing seasons to
spread out the cost.”

Plasticulture in
Georgia

Granberry, an Extension Service vegetable
horticulturist with the UGA College of Agricultural and
Environmental Sciences, said Georgia farmers raise
peppers, squash, tomatoes,
cucumbers and strawberries on plastic-covered rows.

They plant watermelons, also on plastic, in 12- or 18-
inch beds, rather than the 32- to
34-inch beds they grow other produce on. Because of that
difference, they can’t include
melons in the produce rotation that uses plastic mulch
repeatedly.

Most produce grows from planting to harvest in 60 to 90
days. That allows for three
growing seasons each year in much of south Georgia.

The plasticulture
cycle

A typical cycle follows this pattern:

* Lay irrigation drip tape and plastic mulch in one
operation.

* Plant, grow and harvest the first crop. Cut the plant
stems within one inch of the
mulch.

* Cut new holes in the plastic mulch. Plant, grow and
harvest the second crop. Cut the
stems.

* Inspect the mulch for tears and damage from the sun’s
ultraviolet rays. If it’s still
usable, punch new holes and raise a third crop.

* Pull up the mulch and drip tape. Treat the field for
insects or disease problems if
they’re present. Dispose of the plastic. Begin the cycle
again.

Specially developed for
fields

Granberry said the plastic the farmers use was
developed specifically for use in
fields. “The manufacturer incorporates a UV inhibitor that
slows the breakdown of the
material by UV rays,” he said. “Regular plastics, like
garbage bags, break down
relatively fast in sunlight.”

Scientists and plastic mulch makers are working to
learn how to recycle the plastic
mulch after farmers remove it from their fields.

But Granberry said it’s slow going. Soil and plants
stick to the plastic, making the
process expensive and difficult.

“Until we figure out how to get it out of the field
cleanly,” he said,
“recycling isn’t practical.”

But using one application of plastic mulch over several
growing seasons helps cut the
amount of plastic they use.

Benefits of
plasticulture

Using plastic mulch offers many benefits to vegetable
growers. It extends the growing
season by warming the soil faster, so farmers can plant
earlier in the spring.

The mulch keeps moisture in the soil by preventing
evaporation. In-place irrigation
puts water right at the roots, and the plastic helps keep
it there.

Granberry said disease problems are minimal in plastic
fields, too. By watering below
the soil, farmers don’t wet the foliage, where most
disease problems start.

The plastic also keeps weeds around the plants to a
minimum. So farmers don’t have to
use as much herbicide as in bare-ground fields.

Overall, plastic mulch helps farmers produce more,
higher-quality vegetables with the
least added cost.

“It’s harder and riskier to raise vegetables without
plastic,” Granberry
said. “Of course, it’s risky, period, to grow vegetables.
But farmers are looking to
minimize that risk while doing what they can for the
environment.”