Sign up for the
Weekly Harvest Newsletter!

Published every Wednesday, the Weekly Harvest e-newsletter is a free Web digest of sustainable agriculture news, resources, events and funding opportunities gleaned from the Internet. See past issues of the Weekly Harvest.
Sign up here

Sign up for the Weekly Harvest Newsletter

What Is Sustainable Agriculture?

Master Publication List

Search Our Databases

Urban Agriculture

Energy Alternatives

Beginning Farmer

Field Crops

Horticultural Crops

Livestock & Pasture

Value-Added Food Products

Local Food Systems

Food Safety

Marketing, Business & Risk Management

Organic Farming

Pest Management

Soils & Compost

Water Management

Ecological Fisheries and Ocean Farming

Other Resources

Sign Up for The Dirt E-News

Home Page

Contribute to NCAT


Newsletter sign up button

· Privacy Policy · Newsletter Archives

RSS Icon XML Feeds

RSS 2.0: Events, Breaking News, Funding Opportunities Atom: Events, Breaking News, Funding Opportunities


NCAT strives to make our information available to everyone who needs it. If you are a limited-access or low-income farmer and find that one of our publications is just not in your budget, please call 800-346-9140.


How are we doing?


Home  > Question of the Week

Question of the Week

Permalink What information can you give me on college programs and careers in sustainable agriculture?


Answer: I am pleased to provide you with a few resources to assist you in seeking and following a dynamic career in sustainable and ecological agriculture. I have listed several organizations and colleges below that offer programs in this area, as well as the contact information for getting on the COMFOOD listserve, which is a professional email discussion list that includes academics, food system activists, non-profits, schools, farmers, educators, and policy makers, definitely an exciting list to be a part of. Often times apprenticeship opportunities and job openings are announced on the listserve.

Sustainable Farming Internships and Apprenticeships

This directory of on-the-job learning opportunities in sustainable and organic agriculture in the U.S. (and some in Canada) has been published since 1989 as a tool to help farmers and apprentices connect with each other. The listed farms are primarily seeking interns/apprentices from North America.


Center for Whole Communities – Knoll Farm
700 Bragg Hill Rd
Fayston, VT 05673
(802) 496-5690
Programs include Whole Thinking Forums, Vision and Values Workshops, and Measures of Health – an ethically-based, community-oriented standard on why and for whom land is conserved.

Heifer Project International
1 World Avenue
Little Rock, AR 72202
Promotes sustainable development worldwide using livestock and sound environmental practices. Heifer Ranch is a 1200-acre, hands-on educational facility offering internships and volunteer opportunities in livestock, organic gardening, community supported agriculture, beekeeping, agroforestry, and environmental education. Learning centers in Arkansas, California, and Massachusetts; study tours.

New England Small Farm Institute – The Explorer Program
275 Jackson St.
Belchertown, MA 01007
The Explorer Program is intended for those who are considering farming. Its purpose is to help pre-venture, aspiring farmers learn what it would take to start and mange their own commercial agricultural businesses, and decide whether this is a path they really want to take. Its workbook and supporting resources are designed for use in a variety of learning settings: introductory workshops, formal four-session courses, and independent or guided self-study. Created as a decision-making tool, Explorer can help you establish the clear vision and goals you will need to guide a new agricultural venture.

The Intervale
180 Intervale Road
Burlington, Vermont 05401
To develop farm-and land-based enterprises that generate economic and social opportunity while protecting natural resources, through farms programs, community kitchens, farmstead renovation, and farm to school programs.

The Pfeiffer Center for Biodynamics and Environmental Education

260 Hungry Hollow Road
Chestnut Ridge, NY 10977
845-352-5020, ext. 20
Instruction in biodynamic gardening, and organic beekeeping. Workshops, lectures, and courses, including weekend seminars. Training for teachers on how to teach developmental gardening to children. Garden planning and consulting for schools and groups. Internships available.

Agricultural Colleges, Departments, and Courses

The Apprenticeship in Ecological Horticulture
The Apprenticeship in Ecological Horticulture provides training in the concepts and practices of organic gardening and small-scale farming. This full-time program is held at the Center's 25-acre Farm and 3-acre Alan Chadwick Garden on the UCSC campus. Run in conjunction with UCSC Extension, the Apprenticeship course carries 20 units of Extension credit for the approximately 300 hours of classroom instruction and 700 hours of in-field training and hands-on experience in the greenhouses, gardens, orchards, and fields. Tuition for the six-month course is $3,750. CASFS – UC Santa Cruz, 1156 High St.
Santa Cruz, CA 95064, 831-459-3240

Agroecology Program, University of Wyoming

Department of Plant, Soil, & Environmental Sciences, University of Maine

Graduate Program in Sustainable Agriculture, Iowa State University

Sustainable Agriculture Emphasis Area, University of Missouri-Columbia

Sustainable Agriculture Major, Sterling College, Vermont

Sustainable Agriculture Program, Central Carolina Community College

Sustainable and Entrepreneurial Agriculture Program, Marshalltown Community College, Iowa

Center for Agroecology & Sustainable Food Systems, University of California at Santa Cruz

Agroecology Home, Univeristy of California at Santa Cruz

Center for Sustaining Agriculture & Natural Resources, Washington State University

Agroecology/Sustainable Agriculture Program, University of Illinois

Sustainable Agriculture Research and Education (UC-SAREP)

Agriculture and Landscape Program, University of Massachusetts Amherst

Agroecosystems Management Program, Ohio State University

Ecological Agriculture Projects, McGill University

Program in Ecological Agriculture and Society (PEAS), University of Montana

Interdisciplinary Studies Program in Organic Agriculture, Colorado State University

COMFOOD Listserve

COMFOOD is an electronic mail list created to link individuals and organizations involved with or interested in community food security (CFS). The server provides a forum for CFS-related topics. Groups and individuals use this server to share information, to discuss issues, to make technical assistance inquiries, and to share documents that are of interest to subscribers. Educational and professional opportunities are also posted as they become available.

The USDA maintains a list of Educational and Training Opportunities in Sustainable Agriculture on the National Agricultural Library's AFSIC program Web site. It includes college and university programs (but not on-farm programs). The list was last updated in December 2006.



Permalink What can you tell me about soil sampling and testing?


Answer: I am pleased to provide you with information on sampling and testing of agricultural soils for nutrient content.

Farmers test their soils based on their management practices and objectives. Some farmers who grow commodity crops such as wheat, potatoes, or corn, or forages such as alfalfa or grass hay, will test every one to three years. The criteria that determine when a soil should be tested are as various as the types of farms and farmers in America, but in general farmers will test for the following reasons:

• to obtain a baseline of information on nutrient profile of a soil,
• to chart the changes in soil nutrient status, organic matter, and pH due to management inputs, and
• to determine the fertilizer requirement for a particular crop.

Many land grant universities and private labs offer fee-based testing services. For most farmers, the local cooperative Extension agent is the contact for obtaining materials, education, and resources for correct sampling and fertility recommendations. Some Extension agents will even send the samples to the lab, receive them back, and make appropriate fertilizer recommendations on site.

Each state has a cooperative Extension service with agents in most counties. The USDA maintains an online database of local cooperative Extension offices on its website at You will also find the phone number for your cooperative Extension office in the county government section of your telephone directory.

There are also private labs available. The ATTRA website has a list of labs, which can be accessed at The private labs will often offer information on sampling technique and fertility management as well.



Permalink What information can you give me on determining stocking rates for livestock?


Answer: I am pleased to provide you with information on pasture stocking for beef cattle, dairy cattle, and goats in Iowa.

A general rule of thumb for stocking cattle on temperate pastures is one cow to the acre during the growing season, and rotating them periodically between pastures. For intensively managed systems, some Midwest dairy graziers are stocking about 25 cows per acre and rotating them every day to fresh forage. Your stocking rate will depend very much on how intensive your management system is. For this recommendation, I will assume that you will be implementing a controlled rotational grazing system, where animal density is high for a short period of time, and rest periods between grazing are long enough to allow for complete plant regrowth.

It is generally believed that six mature goats equal one cow on improved pastures and that ten goats equal one cow on browse or brushy areas. When grazing brush, it may be necessary to adjust stocking rates in order to accomplish your objectives. For example, when starting out with a very brushy area it might be desirable to stock two to four goats, or more, per acre. Later, as the brush disappears, some goats may need to be sold while a few (one-half to one goat per acre) are kept to control regrowth. These figures depend on the carrying capacity of the land. Observation and adjustment are necessary. Some producers, including Mr. Jim Willingham of 8 Mile Ranch near Uvalde, Texas, choose to allow the goats to harvest the brush as forage and maintain it as a renewable resource, rather than attempting to kill it (Coffey, 2006).

To successfully estimate stocking rate for pastures in Iowa, you will need to obtain information on (1) pasture productivity in tons or pounds per acre and (2) livestock nutrient and intake requirements. This letter contains information to assist you in determining these data and making appropriate stocking rate calculations.

Pasture Productivity for Iowa

Warm season pastures have the ability to yield 2 to 4 tons per acre of forage per year in areas of Iowa where they are adapted. Warm season grass species adapted to Iowa are eastern gamagrass, switchgrass, big bluestem, little bluestem, and Indiangrass.

Cool season pastures for Iowa include tall fescue, orchardgrass, timothy, smooth bromegrass, alfalfa, red clover, and birdsfoot trefoil. Cool season pastures consisting of grasses and legumes are highly productive and will yield as much as 7 tons of forage per acre per year.

Determining Forage Yield and Stocking Rate

Forage yield can easily be estimated with a pasture ruler. A pasture ruler is just that; a ruler calibrated in inches placed on end at ground level, with forage height measured in inches. “One estimate that has frequently been used to relate pasture height to its mass is the rough estimate of 200 lbs. of dry matter per acre per inch of height. This estimate will likely vary 50 lbs. per acre-inch or more based on grass type and season of the year. The height measurement is taken as the “natural, undisturbed height” of the pasture plants adjacent to the measure stick; not stretched or extended” (Barnhart, 1998).

Example: Consider an orchardgrass/legume pasture in good condition, with forage height of 10 inches on average. Orchardgrass should be grazed no closer than 2 inches, so that gives us 8 inches of grazable, high-quality forage. 8 inches of forage height times 250 pounds per acre (in average, good condition) yields 2000 pounds per acre of usable forage.

An 1100 pound cow will consume 2 ½ percent of its body weight per day, so that gives us a forage demand per cow of 27.5 pounds. 2000 pounds of forage supply divided by 27.5 pounds of individual cow forage demand equals 72 cows. This means that each acre of our example pasture has enough forage available to feed 72 cows for one day, or 36 cows for two days, etc.

To realize the efficiencies suggested by these stocking numbers, it is imperative that the farmer implement an intensively managed livestock grazing system. An intensive grazing system controls grazing such that, through high animal impact, the pasture is grazed to a prescribed height and the animals are moved to another pasture to allow complete recovery of grazed plants. The ATTRA publications Rotational Grazing and Paddock Design, Fencing, and Water Systems for Controlled Grazing contain more detailed information to assist farmers in setting up a controlled grazing system.

Another Method for Determining Stocking Rate

A simplified method for determining the initial stocking rate for a pasture of known acreage is to (1) estimate average yield per acre, (2) determine average animal weight, and (3) estimate the length of the grazing season in days. These figures can be used to determine the number of animals that can be grazed in the pasture for the season by using the following formula:

Number of animals = total acreage X yield per acre /
0.04 X (avg. animal weight) X (total days)

Example: Determine number of 1000 pound cows a 50 acre pasture will support for 100 days given pasture yield of 3000 pounds of dry matter per acre…

Number of animals =
50 acres X 3000 lb/ac /
0.04 X 1000 lb X 100 days = 37.5 cows

There are several key issues to consider when thinking about how many animals a pasture will support. Consideration must be given to forage production potential, utilization patterns by livestock, the nutrient content of the forage and forage growth patterns, the plant species that comprise the pasture, species diversity of the pasture plant community, and seasonal variations in temperature and moisture.

Forage Intake by Ruminants

Maintaining high forage intake is the most important thing a farmer can do to ensure high milk and meat productivity in grazing ruminants. Intake is the ingestion of feedstuffs by the animal, and is regulated palatability, foraging behavior, chemical characteristics of the feedstuff, forage quantity, density, and availability, dietary energy and fiber content, physiological stage of the animal, and temperature. For more detailed information on forage intake, see the ATTRA publication Ruminant Nutrition for Graziers, to be published in the fall of 2007. To obtain a draft copy of this publication, email or call 800-275-6228 and ask for Lee.

Options for Increasing Intake on High Quality Pasture

High intake is one of the simplest methods of ensuring adequate nutrition for high producing ruminants. Ensure high forage intake by:

• keeping forage in the vegetative stage through grazing management,
• diversifying pasture composition to include several grass species, with around 30 percent of the pasture in legumes, and
• maintaining a dense pasture so animals will take larger bites.

Intake is maximized when pastures are:

• dense
• digestible
• palatable
• diverse
• correctly stocked
• plentiful (8-10" tall for cattle, 6-8" for sheep)
• familiar to the animal
• fresh (not trampled or manured on)

Pasture Monitoring

Monitoring is the most neglected part of pasture management, and the most important. A good monitoring system will allow you to check how your management decisions are working on the ground. It will allow you to determine, for instance, if a particular grazing plan is having the desired effect over time. A monitoring plan will often involve quantifying a few important evaluation measures, such as plant species composition, percent cover, frequency of species, and forage yield. By comparing these measurements over time, you can start to see trends, and by comparing them to your grazing system, you can alter and adjust where you need to in order to arrive at your goals.

Record keeping is a very important part of pasture monitoring. In addition to recording physical measurements, keep track of when livestock enter and leave a pasture, what if any materials or chemicals are used, re-vegetation or weed control treatments, and observations on cattle health while in the pasture. This information will be extremely useful in refining your grazing plans.

References and Resources:

Barnhart, Stephen K. 1998. Estimating Available Pasture Forage. Iowa State University Extension.

Coffey, Linda. 2006. Meat Goats: Sustainable Production. Butte, MT: NCAT-ATTRA.

Gerrish, J. 2004. Management-intensive Grazing: The Grassroots of Grass Farming. Ridgeland, MS: Green Park Press.

Lyons, Robert K. and Richard V. Machen. 2001. Stocking Rate: The Key Grazing Management Decision. Texas A&M University.

Moore, K. J., T. A. White, R. L. Hintz, P. K. Patrick, and E. C. Brummer. 2004. Forages and Pasture Management: Sequential Grazing of Cool- and Warm-Season Pastures. Agron. J. 96:1103–1111.

Rinehart, L. 2006a. Pasture, Rangeland, and Grazing Management. Butte, MT: NCAT-ATTRA.

Rinehart, L. 2006b. Ruminant Nutrition for Graziers (unpublished manuscript, currently in editing and formatting). Butte, MT: NCAT-ATTRA.



Permalink What can you tell me about greenhouse production, budgeting and marketing?


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

In general, you want to grow a higher value product in greenhouses or hoophouses to offset the labor and cost of setting them up. Lettuce, tomatoes, cucumbers and peppers work well for hoop house and greenhouse production, as it is a fairly high value crop and can be produced off-season for value-added marketing.

Generally hoop houses, or high tunnels, are simple unheated “greenhouse-like” structures that provide less control of environmental conditions than full greenhouses at substantially less cost. They are usually covered with a single layer of plastic and are ventilated only through roll-up sides. A typical high tunnel does not have a heating system, and I do not think it would be necessary in your climate.

In your region, a hoop house would be most effective as a season extension tool in the winter, early spring, and late fall. Over wintering cool season crops, such as lettuce, radishes, and other greens, can be planted in there or you can extend your warm-season crops further into the late fall or earlier in the late spring/ early summer. Also, in your climate the nights get very cold and this type of structure might be helpful for growing tomatoes, which like to have warmer nights than the high desert offers.

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, although certain items would most likely grow year round in a hoophouse in your climate, such as lettuce and cold-tolerant crops in the winter.

I have listed a few greenhouse suppliers that should be able to consult you on different structures and the type (whether you want a greenhouse or hoophouse) 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 shade cloth, just ask them for an estimate of costs.

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. The ATTRA publication “Organic Greenhouse Vegetable Production” estimates 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; hydroponic equipment (if you chose to pursue that type of production) would be an additional $1.50-$2.00 per square foot; land cost, site preparation, foundations, concrete floors, and utilities would be an extra $3.50-$4.00 per square foot.

Listed below is an enterprise budget for tomatoes. This should help as a guide for developing your own enterprise budget. You can adjust the prices according to your situation—e.g. whether or not you would like to do hydroponic production (which is significantly more expensive), and what type of greenhouse structure you choose. The enterprise budgets are simply used as a baseline for you to put your own numbers in based on your research on price estimates.

I have referenced the ATTRA publication “Organic Marketing Resources.” This resource has several different venues for marketing your produce. While this publication is designed for marketing organic products, the venues listed might be open to commercial greenhouse sales, organic or not. 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. If you are interested in producing organically, let me know and we can help get you started on that tract. I have also listed a few basic publications on marketing greenhouse products. “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.

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

Anon. 2006. Greenhouse Tomato Enterprise Budget. Louisiana State University Agriculture Center.

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

Further Resources:
Anon. 2006. New England Vegetable Management Guide. University of Massachusetts Cooperative Extension.

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

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.



Question of the Week Archives