August 31, 2004: When torrential rains threatened
to turn western Iowa into this nation’s sixth Great Lake
one June about 30 years ago, a reporter from The New York Times
phoned then Iowa Secretary of Agriculture Robert Lounsberry
for the straight scoop.
It being an election year and all, Lounsberry spared
no soggy detail in painting a convincing word picture of the
impending disaster. But when Lounsberry had finished, the
reporter floored him with a totally unexpected question: “Mister
Secretary, I don’t understand. When it started raining
so hard, why didn’t the farmers cover their fields?”
Don’t laugh. That really happened. The big city reporter
just couldn’t grasp the difference between, say, the
infield at Yankee Stadium and acres and acres of acres and
acres in the middle of the Corn Belt.
Today, though, such a comment might not seem quite so silly
or naive, especially to innovative producers of high-value
crops such as cut flowers, raspberries, strawberries and fresh-market
and heirloom tomatoes.
Since just 1996, a new type of greenhouse, “Haygrove
Tunnels” from England (www.haygrove.co.uk),
lets farmers literally “cover their fields,” as
the reporter suggested. The tunnels guard against rain, wind,
hail, frost and even disease. They also provide support for
shade cloth and bird netting.
Although pricey -- $26,000 to $28,000 for one acre -- Haygrove
Tunnels quickly pay for themselves by extending the growing
season in spring and fall, and increasing yield, quality and
income, while reducing chemical and labor costs, growers say.
In fact, the tunnels have eliminated the use of soil fumigants
such as methyl bromide on strawberries. Haygrove has 220 acres
of small fruit and flowers -- 55 acres certified organic
-- covered by the tunnels at its farm in England. Worldwide,
Haygrove Tunnels now cover more than 4,000 acres in 12 countries.
Melanie and I have been dying to see Haygrove Tunnels in
person ever since Lynn Byczynski wrote about them last year
in her Growing For Market newsletter www.growingformarket.com.
Unlike our little hoophouse and two larger “ high tunnels”
that you have heard us sing the praises of, Haygrove Tunnels
let producers grow under cover by the acre -- or by the hectare!
Our largest structure, a 30- by 96-foot high tunnel, covers
only 2,880 square feet. Together, our structures cover just
6,240 square feet, or about one-seventh of an acre.
So, soon as we heard about a Haygrove field day at Steve
Groff’s Cedar Meadow Farm (www.cedarmeadowfarm.com)
on Aug. 3, we decided to go. It was well worth the 180-mile
round-trip drive to western Lancaster County.
Groff raises vegetables and field crops on 175 hilly acres
about one mile east of the Susquehanna River. To reduce erosion,
improve water quality and reduce chemical use, he has pioneered
what he calls a “Permanent Cover Cropping System”
that includes no-till, cover crops and crop rotation. Groff
is in his second year of using Haygrove Tunnels. He has six
inter-connected bays. (At least three adjoining tunnels are
needed for structural strength.) Each is 24 feet wide and
300 feet long. Together, they cover about one acre.
The results at Groff’s farm are nothing short of phenomenal.
For example, despite the early arrival of late blight in the
eastern United States and Canada this summer, Groff’s
tunnels yielded more than 1,800 boxes of tomatoes (by Aug.
16) -- 80 percent of them grading out at No. 1. His unprotected
fields yielded only about 40 percent No. 1s.
In addition to doubling yields of top quality tomatoes, Groff’s
Haygrove Tunnels have reduced the farm’s fungicide use
by more than 50 percent and allowed harvest to begin two to
three weeks earlier.
The tunnels also extend the growing season well into fall.
Workers at Groff’s farm used to go home to Mexico around
the time of the first frost. Tomato harvest from the tunnels
last year lasted until Nov. 3, three weeks later than from
“We’ve really fallen in love with the Haygrove
Tunnels,” says Farm Manager Chad Wayne. “Crop
quality is excellent.”
Unlike more traditional high tunnels, Haygrove Tunnels are
only 3-season structures. They are not designed to be used
through the winter or support any snow or ice accumulations.
A single layer of greenhouse poly is secured with ropes and
clips. Sides and ends can be completely opened for ventilation.
The poly can also be vented up to the ridge to prevent excessive
heat build-up. At the end of the season, poly is removed by
bunching it in the gutters where tunnels connect. Greenhouse
film is wrapped in black mulch plastic and secured with twine.
Also, Haygrove Tunnels require no excavation or site leveling.
In fact, naturally sloping ground is often put to use -- with
tunnels running up and down hillsides -- to take full advantage
of naturally occurring air movement, says Ralph Cramer, who
introduced Haygrove Tunnels to the United States a few years
Cramer raises 50 acres of cut flowers in Elizabethtown, PA
posiepatch.com). He first chanced across the tunnels in
a magazine article. After visiting England to see the tunnels
in person, Cramer said Haygrove invited him to introduce them
to the U.S. market. He is now Haygrove’s eastern regional
manager in the United States. So far, Cramer has sold tunnels
to growers from Hawaii to Nantucket Island in Massachusetts.
“The man in Hawaii is growing watercress in tunnels.
He is on the rainy side of the island, where it rains too
much. Watercress grows in water, but it can’t take too
much rain,” says Cramer.
There is a definite learning curve when growing under cover.
“For example, I had to learn what flowers sell for more
money,” explains Cramer. He has about one acre of tunnels
at his farm.
Here are some other features that set Haygrove Tunnels apart
from traditional high tunnels:
They do not need lumber for hipboards on roll-up sides
The tunnels are more easily accessible to field equipment
because of their larger size and ends that open completely.
Y-shaped legs are tipped with an auger or ground screw
to keep the structure from lifting out of the ground, as
sometimes happens with free-standing high tunnels.
After his tunnels were buffetted by Hurricane Isabel in 2003,
Groff added extra ground anchors at the ends of his tunnels.
He tied the tunnel frames to the anchors with heavy-gauge
wire. Although heavily vented frames have withstood wind gusts
of up to 70 mph, Haygrove recommends removing greenhouse poly
when hurricane force winds are expected.
“We copied Haygrove’s method of producing strawberries
and covered the soil (beds, walkways and leg rows) with black
weed barrier landscape cloth and cut holes for the transplants,”
says Groff. “The landscape cloth not only eliminates
all weeds, it reduces condensation inside the tunnels. We
like it so much that it will be a permanent addition to our
program. At the end of the season, we’ll remove the
plant trash and leave the stakes in place for next year.”
Groff transplanted Mountain Spring tomatoes into the tunnels
on April 20 this year. The plants were spaced 20 inches apart
in raised beds on 5-foot centers. There is one stake for every
two plants and five to six woven strings. The extra support
is necessary because tomatoes in the tunnels grow more vigorously
than field-grown plants.
“We got excellent pollination by venting the tunnels
on windy days (which helps remove humidity, toughens the plants
and restricts their height) and by using bumble bees. We’re
not sure how much difference the bees made, since we had plenty
of windy weather, but they’re cheap insurance.”
Haygrove now sells “Luminance” THB (thermal heat
barrier), a 6 mil, three-year poly from Visqueen. The poly
restricts infrared light and cools summer crops by seven to
eight degrees. It also diffuses light better so that light
penetrates the plant canopy more completely, increasing photosynthesis.
Luminance poly costs about 10 percent more than regular greenhouse
plastic. Research has shown the poly increases yields by 20
percent in strawberries and 40 percent in lettuce.
Despite the expense, Groff says he expects his tunnels to
easily pay for themselves in just two to three seasons.
After returning home, Melanie and I began looking at the
potential for growing under cover in our own fields in a whole
new light. And therein lies the problem: We quickly identified
two sites that would be perfect for Haygrove Tunnels for both
vegetables and cut flowers.