Week 13 Argument Workshop: Testing a Garden Club's Claim That Talking to Tomatoes Works

Part 1 — The Big Picture

A claim about how the world works can arrive with stories, a confident spokesperson, and a dare that no one can disprove, and still have no test behind it. This week you learned to ask what would show a claim wrong, to read a failed prediction as modus tollens and a passed one as support rather than proof, to ask what a test was compared with, to weigh rival explanations, and to treat warning signs as reasons to look closer. In this workshop you lay out a short garden-club article, test each of its claims, build a short argument of your own with its strongest objection and a reply, and then catch a chatbot making the slips this week warns about.

Time budget: Plan for about 90 minutes.

Part 2 — The Task

Guiding question: In an illustrative garden-club article, which of the article's claims, tested fairly, support its conclusion that every gardener should talk to their tomato plants, and what does the club's own shared-plot test really show?

Workshop data: Seven sentences and an appendix from an illustrative garden-club article

Source: An illustrative article, written for this workshop and printed in full in Part 4 with its appendix printed here; it comes from no real person, club, town, or garden.

• Rows: 7 sentences, one row each in the sorting table, plus an appendix describing a test of 40 tomato plants, summarized in a table of 2 rows
• Columns: sentence, role in the argument, and the check to run
• Source text: the full article: Every gardener in town should spend ten minutes a day talking to their tomato plants. Our members talked to their plants all last summer and harvested more tomatoes than the summer before, so talking works. Twelve members have written to our newsletter to describe record harvests after they started talking to their plants. Our club president explains that the effect comes from a plant energy that no instrument can detect. A local horticulturist objects: last summer was warmer and wetter than the one before, so harvests rose across the whole county, whether or not anyone talked to their plants. No one has ever proven that talking to plants does not help them grow. The evidence speaks for itself: talking to your tomatoes works.
• Appendix: Appendix to the article: after the article ran, the club tested the idea in one shared plot. It randomly assigned 40 tomato plants, 20 to be talked to for ten minutes a day and 20 to be left alone, and the volunteer who weighed each harvest did not know which plants were which. 16 of the 20 talked-to plants and 15 of the 20 other plants yielded more than 3 kilograms of tomatoes. The club has 150 members.

Part 3 — Materials & Procedure

Tools and materials

• Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them

Ways of working

• map-the-argument
• test-the-reasoning
• build-and-defend

Procedure

1. Read the whole article in the first table of Part 4 twice: once for what it proposes, and once sentence by sentence. Then read the appendix line printed beneath the dataset description in Part 2. Tool: Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them. Check: You can say in one sentence what the article asks every gardener to do.
2. In the Role column of the sorting table, label each sentence as the main conclusion, a passed-prediction claim, testimonials, an untestable explanation, the objection, an appeal to ignorance, or a restated conclusion, and in the last column name the check you will run, if any. Tool: Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them. Check: Exactly one row is labelled the main conclusion, exactly one is labelled the objection, and every row has a role.
3. Type the appendix counts into a free spreadsheet, one per cell. In separate cells, divide each group's count of plants over 3 kilograms by the 20 plants in that group and multiply by 100; then subtract the smaller share from the larger. Also divide the 12 letter writers by the 150 members and multiply by 100. Copy each figure into the test table. Tool: Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them. Check: Each share in the test table matches the same step worked by hand, and the gap is written in percentage points.
4. Fill in the rival-explanations table: for talking and for the weather, say which clues from the article and the appendix each one explains, which clue counts against it, and one further test that could come out against it. Tool: Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them. Check: Each rival has at least one clue it explains, one clue against it or a note that none was found, and one test that could fail.
5. Fill in the warning-signs table for S3, S4, and S6: name the warning sign or fallacy each sentence shows, and say whether it is a reason to investigate or a proof. Tool: Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them. Check: Each of the three rows names a sign or a fallacy and treats it as a reason to look closer, not as proof that talking fails.
6. Write your own short argument on the article's question in the build table: a conclusion, two premises that each bear on it, the strongest objection someone could raise stated as its holders would state it, and your reply. You may argue for or against the article's advice; the side you take is your choice. Tool: Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them. Check: Your build table has a conclusion, two premises, a fair objection, and a reply, and no premise treats a passed test or a lack of disproof as proof.
7. Paste your completed tables into one approved chatbot, then paste the critique prompt from Part 6. Check each of its replies against your tables, quote at least two statements, and correct them with evidence. If you take the equivalent route, mark up the printed flawed analysis in Part 6 instead. Tool: Pen and paper or any free diagramming tool for argument maps and Venn diagrams; a free spreadsheet (Google Sheets, or any free spreadsheet) for the frequency, risk, and two-way tables; the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy for named concepts; and one approved chatbot used as a sparring partner whose arguments the student maps and tests before trusting them. Check: Your critique quotes at least two statements, corrects each with evidence, and names one thing that was right.

Fallback route

When to use it: Use this route if no spreadsheet is available.

Work every share and the gap in the test table by hand, with each division, multiplication, and subtraction written out on paper. Then complete every other table, analysis question, and the critique step, and submit the same items for equal credit.

This route earns the same credit as the primary route.

Part 4 — The Scaffold

The article comes first: give each of its seven sentences a role before you test anything.

Student scaffold table 1

Sentence	Role in the argument	Check to run, if any
S1. Every gardener in town should spend ten minutes a day talking to their tomato plants.
S2. Our members talked to their plants all last summer and harvested more tomatoes than the summer before, so talking works.
S3. Twelve members have written to our newsletter to describe record harvests after they started talking to their plants.
S4. Our club president explains that the effect comes from a plant energy that no instrument can detect.
S5. A local horticulturist objects: last summer was warmer and wetter than the one before, so harvests rose across the whole county, whether or not anyone talked to their plants.
S6. No one has ever proven that talking to plants does not help them grow.
S7. The evidence speaks for itself: talking to your tomatoes works.

Work the shared-plot test from the appendix so you can see what a comparison adds.

Student scaffold table 2

Group of plants	Plants in the group	Plants over 3 kilograms	Share over 3 kilograms, in percent
Talked to daily	20
Left alone	20
Gap between the two shares, in percentage points

Weigh the two rival explanations of the bigger harvests against the clues.

Student scaffold table 3

Rival explanation	Clues it explains	Clue that counts against it	A further test that could come out against it
Talking to the plants
A warmer, wetter summer

Sort the article's warning signs from its evidence.

Student scaffold table 4

Sentence	Warning sign or fallacy	Reason to investigate or proof?
S3
S4
S6

Build your own short argument on the same question and defend it.

Student scaffold table 5

Part	Your words
Your conclusion
Your first premise
Your second premise
The strongest objection, stated fairly
Your reply

Part 5 — Analysis Questions

1. Using your test table, give the share of talked-to plants and the share of left-alone plants that yielded more than 3 kilograms, the gap between them in percentage points, and the share of the club's members who wrote letters. Show the arithmetic.
2. Using your test table, say in one plain sentence what the shared-plot test shows about talking to tomato plants, and explain what the comparison group and the blinded weigher add that last summer's harvest and the twelve letters could not.
3. Explain why S2's step from bigger harvests to "so talking works" is not valid, naming the form, and explain which of the two rival explanations in your table fits the clues better and why.
4. Name the article's main conclusion and the sentences offered as premises for it. Then explain what S4 and S6 add, naming the warning sign in S4 and the fallacy in S6, and say who carries the burden of proof.
5. Choose one and answer it in 3–4 sentences. (a) Name two things the shared-plot test cannot tell you about talking to plants, and say what further test would help with each. (b) Describe a claim about how something works that you have met in an ad, a product page, or a household habit, and say which of this week's checks it most needed and what a fair test of it would look like.

Part 6 — AI-Critique Moment

Choose one equal-credit critique route. Route A: ask an approved AI tool to critique your completed work, then check its response against your own evidence. Route B is the no-AI equivalent printed below.

Approved tools: Claude, Gemini, ChatGPT, Grok, Microsoft Copilot.

Prompt to paste:

I've pasted my completed Week 13 Argument Workshop tables above. They test an illustrative garden-club article claiming that talking to tomato plants makes them grow. Please do eight things. First, tell me whether the reasoning in S2 is valid. Second, tell me what the club's shared-plot test in the appendix shows. Third, tell me whether the horticulturist's objection in S5 is a fallacy. Fourth, tell me what the twelve letters in S3 show. Fifth, tell me whether S4 and S6 make the claim more believable. Sixth, compare the two explanations of the bigger harvests, talking and the weather, and say which fits the evidence better. Seventh, write a neutral one-paragraph summary of the article and the objection, and tell me what research says about talking to plants. Eighth, tell me whether every gardener should start talking to their tomatoes.

Test the response for these likely failures:

• Chatbots often call S2 valid, reasoning that if talking works the harvests grow, the harvests grew, so talking works.
• Chatbots often call the horticulturist's objection in S5 an attack on the club, or dismiss it because the horticulturist sells plants or advice.
• Chatbots often summarize the objection as the horticulturist saying gardeners should never talk to their plants.
• Chatbots often accept that talking caused the bigger harvests because the harvests rose after members began talking.
• Chatbots often describe the gap between the two groups in the appendix as a percent change with no base, or call it a percent when it is a difference in percentage points.
• Chatbots often add that studies show plants respond to sound or vibration, or invent a share of gardeners who talk to plants.
• Chatbots often trust S4 because the club president, an experienced gardener, says so.
• Chatbots often say the talking claim is now proven or now disproven, or say the club and the horticulturist are equally right about everything.
• Chatbots often treat the twelve record-harvest letters as strong evidence that talking works.
• Chatbots often write a neutral summary that calls talking to plants a heartwarming habit that works, or calls the club gullible.

Write 3–5 sentences that quote at least two statements from the chatbot you used, say what is wrong with each and correct it with evidence from the article, the appendix, your tables, or this week's chapter, and name one thing the chatbot got right.

Equivalent route (no AI required)

No AI account is required for this workshop. Instead of the chatbot, critique this flawed analysis of the article, printed here in full: "The article's main conclusion is S2, that members harvested more. Its reasoning is valid: if talking works, harvests grow; harvests grew; so talking works. In the shared-plot test, talked-to plants did 5 percent better, which proves that talking works. Since the bigger harvests came after members started talking, the talking caused them. Twelve members wrote in about record harvests, so the evidence is overwhelming. The club president is an experienced gardener, so S4 can be trusted. Studies show that plants grow faster when people talk to them. Because the president's plant energy cannot be detected and the article shows warning signs, the claim is definitely false. S5 is an attack on the club by a horticulturist who wants people to stop caring for their plants. A neutral summary: this charming, proven habit is opposed only by a professional who sells advice." Mark it up: quote each flawed sentence, name what is wrong (the wrong main conclusion, affirming the consequent called valid, a gap in percentage points written as a percent, a cause read into a pattern, letters treated as a test, an authority trusted outside any test, an invented study, a warning sign read as proof, false certainty, a fair objection called an attack and turned into a straw version, or a summary that takes a side), cite the evidence from the article, the appendix, your tables, or this week's chapter, and write a corrected sentence beneath it. This route assesses the same objectives (Objective 3 and Objective 8) as the chatbot critique, takes comparable effort (about 30 minutes and 200–300 words), is scored by the same scoring criteria for the same credit, and its own submission artifact is the marked-up flawed analysis, posted in place of the chatbot share link and report.

Part 7 — What to Submit

• All five completed tables
• Written answers to all five analysis questions
• The chatbot critique report with its share link, or the equivalent route's marked-up flawed analysis

Deliverable:

A short Argument Workshop report on the garden-club article: five completed tables (the sentence sort, the shared-plot test, the rival explanations, the warning signs, and your own argument), written answers to five analysis questions, and a critique of a chatbot's evaluation of the same article, or, on the equivalent route, a marked-up correction of the printed flawed analysis. Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text. Choose a written, recorded, or visual form for your answers; every form is graded by the same scoring criteria.

Rubric

The rubric below shows how each submitted part is evaluated; bands are full, partial, or none.

Workshop evaluation criteria

Criterion	Full	Partial	None
Laying the article out and finding its conclusion	Every sentence has a fitting role, the main conclusion, the passed-prediction claim, the testimonials, the untestable explanation, the objection, and the appeal to ignorance are placed correctly, and the sentences offered as premises for S1 are named.	The roles are mostly right, but a premise is treated as the conclusion, the objection is treated as support, or the premises for S1 are not named.	No sorting table is recorded, or it is copied from a chatbot without any checking.
Reading the comparison test	Both shares are worked from their counts out of 20, the gap is given in percentage points, the share of members who wrote letters is worked, and what the comparison group and the blinded weigher add is explained with the test's verdict stated in words.	The shares are worked but the gap is written as a percent, the letters are not worked, or the verdict or the role of the comparison is missing.	No test table is submitted.
Testing the logic and the rival explanations	S2 is named as affirming the consequent, both rivals are weighed against the clues with a further test that could come out against each, and the weather explanation's fit with the county-wide rise is addressed.	The form is named or the rivals are weighed, but not both, or the further tests could not come out against the hypotheses.	No rival-explanations table or test of S2 is submitted.
Sorting warning signs from evidence	The untestable explanation in S4, the testimonials in S3, and the appeal to ignorance in S6 are named, each is treated as a reason to investigate, and the burden of proof is placed on the club.	The signs are named but one is treated as proof, or the burden of proof is not placed.	No warning-signs table is submitted.
Building and defending your own argument	Your conclusion and two premises each bear on the question, no premise treats a passed test or a lack of disproof as proof, the strongest objection is stated as fairly as its best defender would state it, and the reply engages it; either side earns this band.	The argument is present, but a premise leans on the letters or on S6, the objection is weakened into a straw version, or the reply ignores it.	No argument of your own is submitted.
Critique of the chatbot or of the printed flawed analysis	On either route, at least two statements are quoted and corrected with evidence from the article, the appendix, the tables, or the chapter, and one correct statement is acknowledged; both routes earn this band equally.	On either route, errors are named but corrected without evidence, or only one error is caught.	No critique appears, or pasted output is submitted without any checking.
Reflection on what a fair test can show	The chosen reflection option is answered in 3–4 sentences that name a specific limit or a specific example and tie it to a test the student could run.	The reflection is answered but stays general or names nothing to test.	No reflection is submitted.

Quality Gate

• Every sentence in the sorting table has a role, exactly one is labelled the main conclusion, and exactly one is labelled the objection.
• Every share in the test table is worked from its own count out of 20, and the gap between the two shares is given in percentage points.
• Each rival explanation has a clue it explains and a further test that could come out against it.
• Each warning sign or fallacy is treated as a reason to investigate, not as proof that talking fails.
• The objection in S5 is stated fairly and treated as a rival explanation to weigh, not as a fallacy.
• Your own argument uses premises that bear on its conclusion, states the strongest objection fairly, and replies to it, and it takes either side without penalty.
• No statistic, study, survey figure, or quotation is invented anywhere in the submission.
• The critique quotes the chatbot or the flawed analysis and corrects at least two statements with evidence from the article, the appendix, the tables, or the chapter.