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Home  > Question of the Week

Question of the Week

Permalink What information can you give me on greenhouse production?

New York

Answer: I am pleased to provide you with information regarding greenhouse production, budgeting, and marketing.

In general, in is important to consider growing higher value products in greenhouses to offset the labor and cost of setting them up. Lettuce, tomatoes, cucumbers and peppers work well for greenhouse production, as they are fairly high value crops and can be produced off-season for value-added marketing.

Greenhouses typically have an insulative layer either by using two layers of plastic or by buying a rigid polycarbonate in sheets. The greenhouse is used for starting transplants and growing things year around. This is what you indicated as your preference.

I have listed a few greenhouse suppliers that should be able to consult you on different structures and the types that would work with the specific goals of your organization. I would encourage you to shop around for supplies and shipping costs. Shade cloth will significantly reduce your cooling costs in the summer and I would urge you to incorporate the costs of this into your budget. The suppliers that I list below all carry shadecloth, just ask them for an estimate of costs.

The Texas A&M publication “Greenhouse Vegetable Guide” discusses the various greenhouse structures. If you would like to do year-round production, you will need a heating system for the winter time. This should be accounted for in your enterprise budget. This is a 137 page publication that covers many topics related to greenhouse production.

There is very little information out there on using compost to heat greenhouses. The hall mark publication was from the New Alchemy Institute in the late 1980’s and their plans are listed in the Compost Heated Greenhouse publication. In this publication they list amounts of compost needed for their plans on page 11. See the following link:

There appears to be very little of this happening on a large scale and perhaps it is because the issues of excessive CO2 and Nitrogen from the compost have not been worked out. I would encourage you to contact the folks at BioCycle (contact information is listed below under further resources) to see if they could recommend consultants in manufacturing a compost heated greenhouse. I have listed below greenhouse sales and consultants, but these suppliers are for regular greenhouses.

Enterprise Budgets
Whatever structure you decide on, it is very important to consider the costs and potential earnings of your enterprise. There are several enterprise budgets available for greenhouse tomatoes and other vegetables. Greenhouse vegetable yields determine potential gross sales. I have sent you production information on several different greenhouse vegetable crops. Much of the information in this letter is referenced from the ATTRA publication “Organic Greenhouse Vegetable Production.” I would encourage you to read this publication if you have not already. I have listed it as a reference along with a direct link below under “references.” This is a good introduction to the considerations you should make when planning a greenhouse operation. The authors estimate that typical yields of greenhouse tomatoes are 20 to 30 lbs. per vine, or 2-3 lbs. per square foot. Greenhouse cucumbers yield around 2 dozen fruits per vine. Greenhouse peppers yield 2½ -3 lbs./sq. ft. A study conducted in Missouri in the winter of 1995-96 showed that supplemental lighting of tomatoes increased total yields from 12,444 kg to 18,840 kg. Because the lighted tomatoes were larger, they brought a better price and resulted in additional revenues of $25,000.

Prior to sinking lots of money into a greenhouse venture, growers should examine produce prices in their region and estimate their cost of production. Historically, the breakeven price for most greenhouse tomatoes has been around 75 cents per pound, with selling prices ranging from 90 cents to $1.60 per pound. The break-even price for cucumbers is similar–around 75 cents per pound.

Estimates of net income from conventional greenhouse tomatoes range from $3,100 to $18,500 per greenhouse unit. These estimates are for good yields and favorable market conditions. Low yields, or a dip in the market, can lead to negative returns to the grower.
The following estimates from 1994 are associated with a double polyethylene greenhouse: the greenhouse itself would cost about $6-$7 per square foot; land cost, site preparation, foundations, concrete floors, and utilities would be an extra $3.50-$4.00 per square foot.
The ATTRA resource list “Greenhouse and Hydroponic Resources on the Internet,” contains several enterprise budgets for regular greenhouse crops (i.e. not hydroponic).

The type of marketing that you may want to consider depends on the scale of your production. If you are planning on growing a few acres of greenhouses, then you might want to spend less time marketing through wholesale marketing. Since you are interested in producing organically, ATTRA can help get you get started on that tract, with many publications and resources on regulations, record keeping and organic production topics. A few basic publications on marketing greenhouse products is listed below under “Further Resources,” with direct links to the publications. “Marketing Strategies for Vegetable Growers” discusses both direct marketing and wholesale options for vegetable growers and “Selling your Greenhouse Tomatoes” which discusses some basic considerations in marketing.

Further Resources:

Anon. 2006. Greenhouse Tomato Culture. Garden Centre. Org

Born, Holly. 2004. Organic Marketing Resources. ATTRA/ NCAT Publication #124

VanSickle, J.J. 2006. Marketing Strategies for Vegetable Growers. University of Florida IFAS Extension. Publication # FRE144

Koske, Thomas. 2005. Selling your Greenhouse Tomatoes. Louisiana State University Agriculture Center.

610-967-4135 ext.22

Greenhouse Suppliers:

Growers Supply, Inc.
1440 Field of Dreams Way, Dyersville, IA 52040

Griffin Greenhouse & Nursery Supplies, Inc.

5612 Pride Road
Richmond, VA 23224-1028
Tel: (804) 233-3454 | Fax: (804) 233-8855

Greer and Diver. 2000. Organic Greenhouse Production. Horticulture Systems Guide. ATTRA/ NCAT Publication # IP078.



Permalink What information can you give me on late blight in tomatoes?


Answer: I am pleased to provide you information on tomato diseases; in particular, late blight and blossom end rot.

Late blight is caused by the fungus Phytophthora infestans. A fact sheet from Ohio State University is referenced below and provides a succinct description of late blight in potatoes and tomatoes. The essential points are that late blight is spread through overwintering inoculum such as tomato vines and leaf debris, through transplants, and through climate related conditions. Thus, sanitation is an important first step. Secondly, when weather conditions are prime for late blight development a protective spray is needed during the growing season.

Spray mixtures of hydrogen peroxide, copper sulfate, and foliar fertilization are fairly effective in controlling late blight. In fact, these kinds of mixtures are what many other organic growers are using. However, there is a lack of efficacy data on what combinations of foliar materials are effective for tomato diseases. Farm-made biological teas and foliar sprays include Compost Teas (CT) and Effective Microorganisms (EM). Compost teas and EM influence the biologically active zones surrounding the plant leaf (phyllosphere) and root surfaces (rhizosphere). The beneficial microorganisms in CT and EM compete with pathogenic organisms that cause plant disease problems, and through various biocontrol mechanisms. ATTRA has additional information on these two topics, available on request.

Serenade, a biocontrol product containing Bacillus subtilis (QST 713 Strain), is manufactured by AgraQuest, Inc. in Davis, California. Serenade is labeled for tomatoes, and it has the late blight pathogen, Phytophthora infestans, listed as a target pest.

ATTRA has two publications that deal with late blight. The first publication is titled Organic Alternatives for Late Blight Control in Potatoes. The second publication is titled Organic Tomato Production and contains information on late blight as well as blossom end rot. Also see Late Blight Resources from ATTRA.


Rowe, Randall, Sally Miller, and Richard Reidel. 1995. Late Blight of Potato and Tomato. The Ohio State University Extension Fact Sheet. Columbus, Ohio: The Ohio State University.



Permalink Can ducks be used in a rotational grazing system?


Answer: Thank you for contacting ATTRA with your request for information on the addition of ducks into a rotational grazing system.

Ducks can be raised in similar production systems as chickens, and be included in a rotational grazing system. Ducks are considered great foragers, and enjoy the young tender parts of plants that are about 3-4 inches off of the ground. Because of this trait, they fit well in a system where larger animals are foraging ahead and consuming the tops. I don't believe they will break up manure as well as chickens do, and that might be the biggest difference to keep in mind.

Ducks can be moved in a pastured pen or can be raised in a free range system with electric poultry netting to protect them from predators. The number of ducks to be placed in the system might determine the style in which they are raised. The labor put into each system is also divided differently.

A pastured pen is moved once or twice a day while the free range system is left for a few days to a week depending on the size of the paddock. When the paddock needs to be moved, time is needed to take down the electric netting, move the shelter/food/water, and put the electric netting back up in a different location. The following two articles regarding raising ducks on pasture may be helpful. 'Pastured Ducks' by Karma Glos discusses her free range system while Chuck Benhoff's article 'Taking the Salatin Model One Step Further' (Stockman Grassfarmer, April 2000) discusses his experience with raising ducks in pastured pens similar to the ones Joel Salatin uses to raise his poultry.



Permalink What information can you give me on grass-fed beef certifications?


Answer: I am pleased to provide you with information on grass-fed beef certifications. There are a few opportunities nation-wide to certify beef operations to a standard and obtain a label for grass-fed and other management practices. These include the USDA-AMS Grass-Fed Claim, the American Grassfed Association Grassfed Ruminant Standards, and the Food Alliance Certified Grassfed Label. Other programs that certify production according to established guidelines, though perhaps not grass-fed, such as Animal Welfare Audits and Certifications and the Beef Quality Assurance (BQA) program, are detailed on the Animal Welfare Information Center website (see below for contact information).

1. Agricultural Marketing Service. 2007. United States Standards for Livestock and Meat Marketing Claims, Grass (Forage) Fed Claim for Ruminant Livestock and the Meat Products Derived From Such Livestock [Docket No. AMS–LS–07–0113; LS–05–09]. Federal Register Vol. 72, No. 199, Tuesday, October 16, 2007.

The Federal Register as cited above delineates a voluntary grass-fed standard. Producers can participate in such programs as the USDA Process Verified Program or obtain a Food Safety Inspection Service (FSIS) label. Detailed information of the Process Verified program can be downloaded. You can also access a list of official PV suppliers from the above link. Information on FSIS programs, including labeling, can be obtained from or by calling their toll-free hotline at 1-800-233-3935.

2. American Grassfed Association. 2009. Grassfed Ruminant Standards.
American Grassfed Association
POB 461090
Denver, CO 80246
(877) 774-7277
The AGA has partnered with Animal Welfare Approved to conduct third party verification of adherence to their grass fed standards. Click on AGA Certification in- 5 Easy Steps for information on obtaining certification. The standards can be accessed at:

3. Food Alliance Certified Grassfed Label
Food Alliance
1829 NE Alberta, Suite 5
Portland, OR 97211
Food Alliance. 2008. Alliance Producer Certification Program Standards and Procedures Manual. Portland, OR.
Food Alliance is a non-profit organization founded in 1997 that certifies farms, ranches, food processors and distributors for sustainable agriculture and production practices.

4. Animal Welfare Information Center
USDA National Agricultural Library
Audit and Assessment Programs, Certification Programs, Standards and Guidelines, Food Industry Animal Welfare Policies, and International Programs.

5. Agricultural Marketing Resource Center
The Agricultural Marketing Resource Center is an electronic, national resource for producers interested in value-added agriculture. Browse commodities and products, investigate market and industry trends, study business creation and operation, read research results and locate value-added resources.
AGMRC – Branded, Certified, Verified Beef



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