Posted April 6, 2004: The only way farmer Steve
Moore could keep heating costs under control back in the late
1980s was to buy oil for his 2,000-gallon fuel tank on the futures
market. And every 10 days he would also burn through 1,500 pounds
of propane. That’s just the price you pay for doing something
as unnatural as growing off-season tomatoes in the North.
While the early cash flow
was nice, the high energy use and cost just didn’t jive
with Moore’s lifelong commitment to practicing a sustainable
lifestyle. He took the matter to what Gandhi called “the
court of conscience” and decided that some major changes
were in order.
Today, Moore’s two new greenhouses do not use a single
drop of fossil fuel. They can’t. They don’t have
furnaces. But Moore didn’t stop there. His greenhouses
No ventilation fans.
No mechanical vents.
No roll-up sides (not on the outside, anyway; they’re
on the inside).
No tractor or tiller inside.
No shade cloth in summer.
No second layer of plastic (on one greenhouse).
No inflation blower in that single-layer greenhouse.
(His other house does have one inflation blower; it’s
powered by the sun.)
No animal manures in compost that’s used in them.
No chemical pesticides or fertilizers applied to plants,
pests or soil inside.
What Moore’s greenhouses do have is nearly
year-round production of copious quantities of a wide variety
of top-quality produce that commands top dollar. Simple in
design and construction, yet sophisticated in management,
these structures have a truly tiny environmental footprint
and a huge positive economic impact on the farm. They are
now, in a word, sustainable.
Maybe that’s why Moore’s rapidly growing numbers
of students refer to the 53-year-old farmer as the “Gandhi
of Greenhouses.” The comparison is a valid one in many
respects. This one-time conventional greenhouse grower is
a highly principled, patient and sometimes prayerful teacher
who is quietly putting common sense and profit back into small-scale
agriculture. Through the example of his daily life, Moore
is clearly demonstrating that less can be more, with the sum
of the parts being greater than the whole.
There is nothing inherently special about Moore’s greenhouses
themselves. They are the exact same plastic-covered steel
frames utilized by Pennsylvania State University’s Center
for Plasticulture. At Penn State and a dozen other land-grant
colleges around the country, researchers are busily tending
to monocultures of traditional crops like tomatoes, cucumbers
and even potatoes with field equipment inside these greenhouses,
or “high tunnels,” as the scientists call them.
A few not-so-traditional greenhouse crops—berries and
sweet cherries—are also being tested under cover.
Frames for the greenhouses come from the same source, Ed
Person, a New Hampshire farmer who has been using and building
greenhouse frames for about 30 years. (Contact Ledgewood Farm,
Rt. 171, Moultonboro, N.H. 03254. Phone: (603) 476-8829. E-mail:
But that’s where the similarities end. Moore and the
scientific establishment are on two very different paths.
While scientists cut the corners of square-peg field agriculture
to fit the more circular shape of a greenhouse, Moore is developing
a cropping systems based more on natural cycles and consumer
demand than on existing production tools.
Rather than fighting nature, Moore works with the seasons.
He plants a staggering array of cool-season crops in his greenhouses
during the cooler months. Only as the weather warms does he
begin easing in heat-loving crops like tomatoes, peppers and
The results are truly impressive. Moore’s business
plan for a “biointensive lettuce mini-farm,” for
example, reaps a gross income of $25,000 and a net of $20,000.
That’s over a nine-month season—on just one-quarter
of an acre.
Moore held a two-day passive solar greenhouse workshop at
his rural Pennsylvania farm in March. He planned on limiting
enrollment to just 25 students. Many were turned away, yet
the final total swelled to 35. License plates in the parking
lot that weekend were from Pennsylvania, New Jersey, Maryland,
Massachusetts, Vermont, Quebec, Virginia, Ohio, Michigan,
Colorado, and California.
People just can’t seem to get enough of Steve Moore
and his sustainable greenhouse management these days. “I
spent almost every weekend of late February and March lecturing,
here, at Michigan State, at Wilson College’s Sustainable
Development Conference…” Moore says.
“I gave my first presentation on the energy of a sustaining
food system at Wilson. With all my charts and spreadsheets,
I was concerned people would tune me out. I was surprised
at their interest, and it has spurred me on beyond my own
insatiable obsession. That is all past now and it is the time
to buckle down.”
After all, Moore still has a farm to run. Moore and his wife,
Carol, earn their living by farming, not teaching, speaking,
writing or conducting scientific research, although they do
plenty of each. Moore is the farmer at Sonnewald Natural Foods
in Spring Grove, a village about 8 miles southwest of York,
Pa. Sonnewald (Pennsylvania-Dutch for “sunny woods”)
bills itself as perhaps the oldest existing organic farm and
natural food store in Pennsylvania. Its motto is: “Good
health comes from the farm ... not the pharmacy.”
Moore’s next greenhouse workshop is not scheduled until
September 24-25, toward the end of the busy part of the season.
By the end of March, though, that workshop was already more
than three-quarters filled. (Early registration costs $175
per person, single, or $160 per person for two or more people
from the same family or farm. Free on-site dormitory space
Moore simply can’t keep up with the demands on his
time, so he is making plans for another round of workshops
for next winter. Work is also under way on a website and a
manual on how to design, build and operate a passive-solar
greenhouse for year-round food production. The manual will
be available for purchase by mail. (Keep checking NewFarm.org
Why are passive solar greenhouses becoming so popular? The
answer is simple: “Anyone can build one of these and
have fun doing it,” Moore says. But watch out, he adds.
“Greenhouses tend to have a herding instinct. The first
year there is one; the second year, three; the third year,
five. Design for the future, so there is room where you would
want five of these.”
Future growth will help determine the size of the greenhouse
frame you start out with. While some erect a 16- by 96-foot
greenhouse to save money, Moore strongly advises
starting out with a wider, shorter frame, say, a 30- by 48-foot
structure. “It will cost a little more, but then you
can add to it. You will soon regret not having the extra width,”
That makes proper site selection one of the first items in
Moore’s lesson plan. “Accept as much natural energy
as possible, lose as little energy as you can,” Moore
advises. “Store an adequate amount, keep it simple—both
mechanically and in management—and do it with a payback
and minimal risk.”
The prime consideration in all of this is the path of the
sun. “Hills, trees—even deciduous trees that lose
their leaves—and buildings can really restrict sunlight
in the winter when the sun of low on the horizon,” Moore
cautions. That is why he advises carefully evaluating your
site with a good sun chart such the one in Edward Mazria’s
book, The Passive Solar Energy Book (Rodale, 1979). “Unless
you are very attuned to the sun’s movements, you may
be quite surprised at the actual changes over a year’s
time,” he adds.
“Most greenhouses are oriented with the long axis north-south
to avoid shading. In order to accept the most energy, greenhouses
should be oriented east-west to maximize solar gain. Utilizing
a gothic arch design will reduce the shading problem.”
Keep in mind that true south is not the same as magnetic south,
he adds. Where Moore farms in southeastern Pennsylvania, true
south is seven degrees west of magnetic south. “It is
better to orient a little to the east to facilitate more energy
earlier in the day and warm up the greenhouse quicker,”
Other essential considerations include:
Local zoning and other
ordinances. In most places, high tunnels
are considered temporary agricultural buildings and are
exempt from building permits and property taxes.
Good drainage. It is essential.
“Water has to go somewhere,” Moore says. “Once
you have water in your greenhouse, you can’t get
rid of it in the winter. It is absolutely critical to
get water away.”
Moore recommends leveling your building site and, if
necessary, even raising it to provide proper drainage.
Soils can always be improved later with the addition of
compost. “You can take some pretty crummy soil and
make it good,” he reassures students.
Buy only a quality greenhouse
frame. “The better houses have more
purlins [supporting framework] for increased structural
support. Buy a pre-drilled greenhouse frame. Never buy
a frame that is not pre-drilled,” Moore cautions.
“Can I build a frame now (in spring) and cover in
fall?” a student asks. “As long as you don’t
get caught by weather in the fall. Give yourself plenty
of time,” Moore answers. “And remember, you’re
working with 50-foot-wide sheets of plastic. It doesn't
take much wind for them to seem like they have a mind
of their own.”
More about that in the next posting, when Moore
details the finer points of construction and operation of
the passive solar, sustainable greenhouse.