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 have:
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
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: email@example.com.)
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
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 eggplant.
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…”
“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 is limited.)
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 for details.)
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,” he
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,” he says.
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
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
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.
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,