You are here

Key Topics

Use Case Observations from Grinnell Farmers' Market

From my visit to the Grinnell farmers' market on August 11, 2006, I designed both a template for interactions between vendors and customers, and a set of use cases depicting these interactions.

In all interactions between vendors and buyers, there are two constants: the customer walking over to the stand, and the customer leaving the stand. After these obvious aspects of the interaction, there are three variables in any vendor-customer interaction: amount of time spent speaking with the vendor, amount of time spent examining the goods on offer, and the amount of goods ultimately bought by the customer. A fourth variable would be the topics discussed by the vendor and customer (where the goods were grown/made, how much they cost, etc.); unfortunately, my position as an observer did not allow me to watch the interactions closely enough to observe interactions in such detail.

Given this template for buyer-seller interactions, all use case observations differ in only the extent to which each of the three variables is present (I designed the list of constants and variables in buyer-seller interactions following my use case observations, not prior to them. I noticed in my observations that all interactions differed in only these three areas, which induced me to create a list of possible variables). Interactions also differ in the characteristics of the customer and the goods sold at the particular stand.

Some of the more common interactions I observed included: (Though each of these interactions were observed more than once, a common gender/age (ages are my estimates) of the customer is included, along with a typical vendor station where the interaction was observed)

Note: Along with every use case description, I have attached a diagram, located at the end of this document. Description titles correspond with diagram titles (for example, Use Case Observation 1 is depicted graphically in the attached .GIF document with the same name).

Use Case Observation 1: 45 year old female customer glances at goods while passing by produce stand.

(On a scale of 1-10)

Time spent speaking with vendor: 0
Time spent examining goods on offer: 0
Amount of goods bought: 0

Use Case Observation 2: 40 year old male customer talks extensively with vendor at produce stand, then buys a good.

Time spent speaking with vendor: 10
Time spent examining goods on offer: 10
Amount of goods bought: 5 (only one good was bought, but on a scale of 1-10 in the goings-on in the market, this falls in the middle).

Use Case Observation 3: 30 female customer asks question of vendor at crafts station, then leaves.

Time spent speaking with vendor: 2
Time spent examining goods on offer: 2
Amount of goods bought: 0

Use Case Observation 4: 20 female customer buys a good at kettle corn station, without asking any questions.

Time spent speaking with vendor: 0
Time spent examining goods on offer: 1
Amount of goods bought: 5

Use Case Observation 5: 60 female and 60 male customer speak with produce station vendor for a while, while examining goods, then buy a good.

Time spent speaking with vendor: 8
Time spent examining goods on offer: 10
Amount of goods bought: 5

Use Case Observation 6: 50 female customer examines goods at produce station, then buys something.

Time spent speaking with vendor: 0
Time spent examining goods on offer: 8
Amount of goods bought: 5

Use Case Observation 7: 40 female customer examines goods at baked goods station, then leaves.

Time spent speaking with vendor: 0
Time spent examining goods on offer: 5
Amount of goods bought: 0

Use Case Observation 8: 55 male customer speaks with vendor at produce station extensively, then leaves.

Time spent speaking with vendor: 10
Time spent examining goods on offer: 2
Amount of goods bought: 0

Use Case Observation 9: 20 male customer asks a question of vendor at produce station, then buys good.

Time spent speaking with vendor: 2
Time spent examining goods on offer: 2
Amount of goods bought: 5

Use Case Observation 10: 45 female customer asks several questions of vendor at produce station while examining goods, then buys a few different goods.

Time spent speaking with vendor: 8
Time spent examining goods on offer: 10
Amount of goods bought: 10

What crops grow best in Grinnell?

I have been researching online about what crops grow best in the Grinnell and Fairfield areas (in regards to Timlynn's question relating to the Iowa Produce Market Potential Calculator). Though my online research has yielded no results, Jon Andelson sent me some good information in response to an e-mail:

"Among commodity crops, it's pretty clear than corn and soybeans grow best here (compared to wheat, for example, or rice). Corn can be for humans (sweet corn, popcorn), though that's a small part of what is grow here. Soybenas can, too (tofu, soy yogurt, etc.), though, again, that's a small part of what's grown here. On the other hand, wheat can be grown here just fine, as can barley, oats, rye, buckwheat, and other grains. It's just not as profitable as growing corn. Are you interested in crops that are biologically viable, economically viable, or both? Other major crop categories are tree crops (fruits and nuts) and produce (vegetables). And then melons of various kinds. Were you interested in one or another categories, or all of them? Most produce does pretty well. We're near the northern limit for peaches and grapes, but they ARE viable, both biologically and economically. Apples and pears tend to do pretty well. Let me know how/if you want to narrow your focus."

Similarities and Differences Between the Grinnell and Fairfield Farmers' Markets

A statistical analysis of the data I collected from the Grinnell and Fairfield Farmers' Markets. See my more detailed write-ups of the two markets ("A profile of the Grinnell Farmers' Market" and "A profile of the Fairfield Farmers' Market) in earlier blogs for more information.

The Vendors

Total number of stations:

  • Grinnell: 27
  • Fairfield: 23

Total number of vendors:

  • Grinnell: 34
  • Fairfield: 37

Gender of Vendors:

  • Grinnell: 41% male, 59% female
  • Fairfield: 35% male, 65% female

Distribution of Goods:

See Chart1 in "Statistical Comparison of Farmers' Markets" (attached)

Miles Traveled to Reach Market:

See Chart2 in "Statistical Comparison of Farmers' Markets" (attached)

  • Grinnell average: 22.41 miles
  • Fairfield average: 13.91 miles

Frequency of Attendance:

See Chart3 in "Statistical Comparison of Farmers' Markets" (attached)

Percentage of Vendors who Sell at other Farmers' Markets:

  • Grinnell: 43%
  • Fairfield: 35%

Percentage of Vendors who Sell at Places other than Farmers' Markets:

  • Grinnell: 48%
  • Fairfield: 65%

Estimated Ages of Vendors:

See Chart4 in "Statistical Comparison of Farmers' Markets" (attached)

The Customers

Estimated Ages of Customers:

See Chart5 in "Statistical Comparison of Farmers' Markets" (attached)

Miles Traveled to Reach Market:

See Chart6 in "Statistical Comparison of Farmers' Markets" (attached)

Frequency of Attendance:

See Chart7 in "Statistical Comparison of Farmers' Markets" (attached)

A Profile of the Grinnell Farmers' Market

The Grinnell Farmers' Market runs every Thursday, May 27 to October 14, 3-6 PM, and every Saturday, June 5 to October 9, 8:30-10:30 AM. A wide variety of goods are sold at the Grinnell Farmers' Market, including many different types of produce, baked goods, homemade crafts, berries, and even kettle corn. The Grinnell Market attracts buyers and sellers from many miles away; according to one vendor, Grinnell Market presents the best opportunity for sales in the area. Grinnell's Farmers' Market constitutes a large portion of the local food economy. Many vendors are dependent on their farmers' market sales; according to another vendor, "most people's sales are over after the farmers' market season."

There are no market events or activities connected with the market. There is a playground near the market, where children played while their parents shopped.

All market observations are from Thursday, July 20, 2006. This appeared to be a normal session for the Grinnell Market (an observation which was confirmed through discussions with vendors), though it was quite hot outside.

The Vendors

There were 27 stations at the market. Vendors from all but four of these were willing to respond to the six questions that I asked of them; a total of 23 stations are therefore profiled here (while I could've partially profiled those vendors that were unwilling to answer my questions, I chose to leave out those vendors for which I had any information missing).

Each of the stations was set up at opening time (3:00 PM). All but two stayed through to the closing time (6:00) or close to it. The two who left significantly earlier departed at approximately 5:30.

13 of the 23 profiled stations were operated by one vendor, nine were operated by two vendors, and one was operated by three. Of the 34 total vendors, 14 were male and 20 female. Though I decided it would be inappropriate to personally ask the age of each of the vendors, I approximated their ages myself; my guesses are located in Chart1 in the attached Microsoft Excel file entitled "Farmers' Market Vendors." From my estimations, most vendors were between the ages of 31 and 50.

I have divided the goods sold at the market into five major item categories: Baked goods, crafts, flowers/plants, produce, and "other." Common instances of items from each of these categories are below. 10 of the 23 vendors sold from more than one of the above major item categories. The number of stations that sold items from each of these groups is shown in Chart2 in "Farmers' Market Vendors." Produce were the most widely sold goods at the Market.

Baked goods: Cookies, pies, pastries, breads
Crafts: Quilts, paintings
Flowers/plants: Self-explanatory
Produce: Apples, berries, corn, potatoes, onions, beans, lettuce, cucumbers, tomatoes, cabbage, peppers, squash, melons
Other: Includes one instance each of honey, apple cider, jams, bagged snacks, and kettle corn

Vendors came from as close as 1.5 miles and a far as 45 miles. On average, vendors traveled 22.41 miles to sell at the market. Vendors from 19 of the 23 stations traveled between 11 and 38 miles to reach Grinnell. A graph of the miles traveled by each vendor is located in Chart3 in "Farmers' Market Vendors." By examining the license plates around the market before most customers had arrived, I guessed that approximately that about 80% of vendors are from Poweshiek County, 15-20% from Jasper County, and a few from Marshall County.

Nine of the 23 vendors come to the Grinnell Market both days the market is in session; 13 come one of the two days, and one vendor comes every two to three weeks. Of the 23 vendors, 10 regularly sell at other farmers' markets, while 13 do not. Of those who sell at other markets, eight sell in Marshalltown, two in Des Moines, and one each in Conrad, State Center, Toledo, and Union. For those vendors who sell at other markets in addition to Grinnell's, all who commented on their profits (five out of these 11 vendors declined to answer the question) said that Grinnell was the most profitable market they sold at. 11 vendors sell their goods at places other than farmers' markets; the remaining 12 only sell at such markets. Of those who sell at other venues, three sell to institutions (restaurants, Grinnell College Dining Services), eight sell from a house, vehicle, or stand on the road, and one sells at community events (festivals, etc.). All but one of the 23 vendors said that they have a set of loyal customers who regularly buy from them.

Though most vendors declined to say what, if anything, they like or dislike about selling at farmers' markets, a selection of responses include "there are a lot of customers," "you get to meet people, and get to know your customers" (popular), "the money," and "the chance to extend the product line." Only two vendors mentioned anything they disliked about the market: the unpredictable weather, and the parking.

There is a group of six sellers who regularly sell at the Marshalltown Market who come to Grinnell to sell. As the Marshalltown Market has a system in place in which credit cards and food stamps are accepted by vendors, these six vendors bring these their equipment with them and are therefore able to accept such payment.

The Customers

Customers began to arrive at the market about fifteen minutes before the 3:00 opening time. When the market opened at 3:00, there were 10-15 customers who had already began to browse the selection of goods and talk to vendors. These early customers appeared to be split between the 30-50 and 51-65 age groups. All of these early arrivers were women.

Activity at the market peaked between 3:15 and 3:45. According to one vendor, "customers have to come early or they won't be able to buy the freshest, or any, goods." There were about 60 people at the market during its peak period. The number of customers at the market ranged from about 20 (towards the end) to 70 (at about 3:15). On average, there were about 35-40 people shopping at any given time.

Produce stations were the most popular at the market session I attended. Stations selling crafts, as well as those stations without a variety of goods (for example, the one selling honey and apple cider, and the one selling berries) were relatively unpopular. Some customers were friendly with particular vendors – those vendors who were more friendly tended to have more customers around their stations. The location of each station was another factor in the popularity of that station. Some stations were farther away from the main areas of the market, and as a result were less well attended. Those vendors who were away from the main areas of the market were also relative newcomers to the market; this also may have affected their popularity. The typical customer left carrying two bags of goods bought at the market (from this I infer that such customers had bought from two different vendors).

After taking a mental survey of the customers at the market at three different times through the course of the market, I estimated the percentages of customers who were in each age group. My estimates are located in Chart1 of the attached Microsoft Excel document "Farmers' Market Customers."
(Note: Most of those customers in the 18-30 age group I recognized as Grinnell College students).

At approximately the midpoint of the market (4:30), I conducted a short survey using a random sample of customers as participants. I asked 20 customers to take the survey; seven refused, so I have a random selection of 13 customers as my sample. These customers came from as far as 25 miles away and as close as one block away to attend the market. A graph showing the complete responses to this question is shown in Chart2 in "Farmers' Market Customers." Most customers surveyed said that they attend the market weekly, the remaining few said they either come once or twice a month (see Chart3 in "Farmers' Market Customers."

The final question asked of these surveyed customers was "what do you like most about shopping at farmers' markets?" Answers to this question varied, with the only consistent answer being the availability of fresh produce. See Chart4 in "Farmers' Market Customers" for complete responses.

Advertising the Market

In Town

There are a few posters in store windows in town. After looking in the windows in just about every store downtown, I saw posters in three different stores advertising the farmers market in their windows. In addition, I saw similar posters on the indoor walls of two stores. These posters are fairly small (about 8.5x20 in.), colorful, and simply say "Shop at Your Local Farmers' Market," with the dates and times of the market below.

At the College

After walking through the entire campus, I saw only two signs advertising the farmers' market. One was located in the library, the other in a kiosk in central campus. These signs are similar to those in town. They are a bit smaller, and simply grab the attention with "The Grinnell Farmers' Market" in bold letters, then the dates and times of the market below. These signs may well be more plentiful on campus during the academic year; at this time, however, they are sparsely located.

There is also blurb about the farmers' market on the Grinnell College webpage, in the "Things to Check out in Town" section (

Around the Market

There are seven light posts located around the block in which the market takes place. Each of these posts has two very large banners attached to it. They both have "Farmers' Market" written on them in big letters; one says "Thursdays" under it, the other "Saturdays" (the market is in session on Thursdays and Saturdays). With their size, color, and location atop huge light posts, these banners are unmissable when walking or driving around the area. When the market is in session, these banners make it obvious where exactly the market is located. When the market is not in session, the fact that these banners are clustered together in one area makes it clear that the market will be there in the future.

Local Newspapers

There is a small advertisement for the farmers' market in the local paper (The Grinnell Herald-Register). The ad simply mentions the location, and dates and times of the market. There is a similar advertisement in the town's Pennysaver.

During the academic year, the farmers' market is advertised with a small note in the college newspaper, the Scarlet and Black (the paper does not come out during the summer).

The Farmers' Market Staff

The Grinnell Farmers' Market is sponsored by the Grinnell Area Chamber of Commerce. The market is staffed by one person each time it is in session (it is staffed by different people on Thursdays and Saturdays, so there are a total of two different people who staff it throughout the season). These people are volunteers who have chosen to provide assistance at the market. Sometimes these staffers are vendors or farmers; other times they are other people from the community.

The duties of the staff at the market last only while the market is in session. It is his/her duty to make sure that the transactions at the market go smoothly (no fights, etc.). It is also the responsibility of this person to make sure that all goods sold at the market are allowed to be sold there. All produce must be Iowa-grown, and all crafts must be homemade. Nothing that can spoil is allowed to be sold at the market, as it is difficult to make sure that such goods haven't already gone bad. This effectively means that no cooked goods can be sold at the market, with the exception of baked goods; additionally, one man has been given special permission to sell kettle corn.

Comparing my findings from Grinnell's Market to research about Iowa Farmers' Markets

In this section, I will compare my findings to findings from previous research into Iowa Farmers' Markets. In particular, I will use two studies conducted by researchers from Iowa State University. The first of these studies, conducted by Clare Hinrichs from Iowa State University's Department of Sociology, relates to Farmers' Market vendors. Data is obtained from a 1999 mail survey sent to vendors from 24 Iowa Farmers' Markets. Findings are based on 223 completed and returned surveys. Findings from this study are published in a paper entitled "The Experiences and Views of Iowa Farmers' Market Vendors: Summary of Research Findings;" this paper is available online at

The second of these studies was conducted by Dr. Daniel Otto and Theresa Varner, of Iowa State University. Demographic and market participation information in the study was collected from a sample of over 4500 consumers and over 780 vendors during the 2004 season. Surveys were conducted by the Iowa Agricultural Statistics Service; the consumers and vendors from a large sample of markets taken from a list of all Iowa markets were selected to take the surveys. This findings of Otto and Varner's study are published in a paper entitled "Consumers, Vendors, and the Economic Importance of Iowa Farmers' Markets: An Economic Impact Survey Analysis; this paper is available online at

Hinrichs' study reports that farmers' market vendors attended an average of 2.3 markets per week during the peak season. Results from my study indicate that the average Grinnell vendor attends an average of just under two markets per week. Otto and Varner repoted that Iowa vendors planned to attend an average of two different markets during the season. I found that number to be about 1.7.

According to Hinrichs' study, vendors travel an average of 18 miles to reach each market. The average from my study was a similar 22 miles. The extremes that I found (1.5 miles as a lower limit and 45 miles the upper limit), were less extreme than those found in Hinrichs' study (less than a mile to over 100 miles). This is not surprising consider the far greater sample size that Hinrichs used in her study.

Otto and Varner's study reports that Iowa markets were open for an average of 1.4 days for an average of 21 weeks, featuring an average of 13 vendors. Grinnell's is an above average market in this regard: it is open two days a week, for exactly 21 weeks. When I observed Grinnell's market, there were over twice as many vendors (27) as the Iowa average reported in this study. Otto and Varner report that consumers travel an average of eight miles to reach a market, I found an average of slightly over five miles; this is not surprising, as Grinnell is a small (college)town.

Otto and Varner use somewhat different age groupings from those I use in assessing farmers' market customers. They find the ages of market customers to be:

21-35 years: 14%
36-50 years: 25%
51-65 years: 32%
>65 years: 28%

Compare these to the numbers I found:

18-30 years: 20%
31-50 years: 45%
51-65 years: 25%
>65 years: 8%

Otto and Varners' numbers are more precise as they used survey information, while I estimated the ages of customers. This is also, of course, in addition to the greater sample size that they have.

I found the most common age group (from my estimations) for vendors was 31-50 years old; Otto and Varner found the average to be in the 51-65 age range.

"Local Food and Grinnell College Dining Services"

I have just finished reading "Local Food and Grinnell College Dining Services," a report from an independent study group at Grinnell College in the spring of 2006. Professor Jon Andelson (who lent me the report) was the faculty mentor of these students.

The students convincingly make the case that Grinnell College dining services should increase the percentage of local foods it uses from 5.8%. The argument is based upon five principal factors: helping the environment, nutritional value, support for the local economy, cost effectiveness, and student opinion. These factors are roughly in line with GALFA's "Five Reasons to Buy Local": Taste and freshness, food safety, environmental protection, economic health, and connection (for a detailed explanation of these five factors, see

This report helps to serve our ends in two major areas:

  • Firstly, it profiles the Grinnell College student body in terms of its support of local foods. Grinnell College and its students represent an important player in Grinnell's food economy; understanding the views of the College's student regarding the use of local foods will help us develop this player in our game.
  • Secondly, the report contains a chapter entitled "Report from the Interviews with Producers in the Grinnell Area." These producers, like Grinnell College students, are a player in the town's economy. Through the interviews and analysis of these producers and their behavior, we can more accurately characterize this player.

Regarding local food producers, Professor Andelson also gave me a "Directory of Grinnell Area Food Producers Who Market Locally." It may be useful to contact these producers at some point along the line.

Take time to stop and smell the data...

The next step before going too much further would be to do some field work. There is no substitute for direct observation of what you are trying to model.

You should plan to spend a Thursday session at the Grinnell Farmer's Market first, followed by a Saturday morning at the Fairfield market. Ask questions of buyers and sellers, take notes. Keep in mind all that you have been reading and thinking in terms of modeling the market elements. Use the blog space to share how this direct experience shapes your thinking around the system model.

Also before going further on the modeling side of this project, you should do a good bit of on-line research on the local food economy projects here in Iowa. Get a good feel for each project and develop a kind of 'mental model' if you will of how each 'system' is set up.

Identify which projects you are researching in your blog space and capture your thoughts as to what you find. Do you find any kind of "meta model" that most projects seem to follow? Are there any 'stand out' projects you come across? Where are these operating and what makes them stand out? --------- you get the idea. You should be grounding yourself over the next several weeks on the "data" before leaping back into the modeling.

Look at as many examples as you can find from Iowa, but also see if you come across interesting examples from elsewhere (see my blog post on the Michigan Land Use Institute local food economy project).

Let's spend the next two weeks in "data space" - this should help shape our modelling.

Some thoughts about Grinnell's food economy

From Wikipedia (,_Iowa)

There are four grocery stores serving Grinnell.

* Hy-Vee Food Stores - Located on the very far southern edge of town. There is no sidewalk or other way for bikers and pedestrians to get to Hy-Vee. Hy-Vee offers drive-up service upon request (you drive to the side of the store and they will load your car with your packages for you). Hy-Vee is open on Sundays.
* McNally's - This locally owned independent store is the most centrally located grocery store in town. It has the widest selection of gourmet food products as well as a large alcohol section. This store caters to the college crowd and to those looking for upscale or smaller-market products. McNally's has carry out boys and they will also deliver. McNally's is open on Sundays.
* Fareway - This store is slightly west, but still fairly centrally located.
* Super Wal*Mart - Opened in the Spring of 2006, the Super Wal*Mart is the only grocery store open 24 hours a day.


McNally's, the second of the four listed stores, is evidence that shoppers in Grinnell do, indeed, take factors other than price into account when making buying decisions. McNally's prices are higher than those of the other three retailer for nearly every product; if consumers bought strictly based on price, McNally's would've gone out of business long ago. McNally's stays open because of its small business appeal, its long stay in Grinnell, and the sense of community that it helps to foster, among other things. It is proof that a business that caters to something other than their costumers' checkbooks can succeed.

That said, Walmart (and, as of the spring, Super Walmart), dominates the local food economy. It would be interesting to examine the relative market share of McNally's and Walmart over time, to see if buyers are shifting towards or away from the "Walmart brand" of consumerism.