Forget Formula 1. The most anticipated race in Walnut Creek this weekend is powered entirely by vegetables—and the entry fee is whatever a zucchini costs at the farmers’ market.
The Diablo Valley Farmers’ Market brings back its annual Zucchini Car Race on Saturday, June 20, inviting kids, parents, and competitive adults to transform farm-fresh zucchini into gravity-powered race cars for a morning of creative engineering, friendly competition, and $200 in total prize money. The free event lands on Father’s Day weekend, making it a natural outing for families looking for something beyond the standard brunch-and-card routine.
How It Works
The premise is simple and gloriously analog: participants bring a locally-sourced zucchini, show up before 10 a.m., and use the complimentary wheels, axles, and decorating supplies provided by the market to build their entry. The construction zone is part pit crew garage, part elementary school craft table.
Registration closes at 10:45 a.m., and racing begins promptly at 11 a.m., with competitors sending their decorated creations down a custom-built race ramp as spectators line the sides. Cars advance through a series of elimination heats until two champions emerge: one for Fastest Car and one for Most Creative Car, each earning a $100 prize.
The event is designed to be accessible to all ages. Younger children can focus on decorating while parents handle the axle-and-wheel assembly; older kids and teens often treat the competition with the seriousness of an engineering challenge, experimenting with zucchini shapes, weight distribution, and aerodynamic flourishes made from market-supplied craft materials.
The Rules of the Road (and the Zucchini)
Unlike the freewheeling chaos the event’s spirit suggests, zucchini car racing has a specific rulebook—and it is enforced with the seriousness of a tech inspection at Le Mans. The rules exist to keep the competition fair and the playing field level, and they reward creativity within constraints rather than creative rule-bending.
Zucchini must be farm-fresh and sourced from a farmers’ market or local garden. Grocery-store produce is not permitted. The market itself sells zucchini on race day, so even last-minute entrants are covered.
Maximum dimensions: 6.5 inches wide (including wheels) and 16 inches long. Cars exceeding either dimension will not pass inspection.
No weights, no motors. This is pure gravity racing. The axle must pass through the zucchini itself—no external chassis, no ballast, no propulsion of any kind.
Every car must have a name. Registration requires a unique name for each entry. Past winners have included names that suggest considerable pre-race workshopping.
More Than Just Racing
The Zucchini Car Race anchors a broader day at the Diablo Valley Farmers’ Market, where visitors can explore peak-season offerings from local growers while the competition unfolds. June is a sweet spot in the Contra Costa growing calendar, and the market stalls reflect it: Brentwood sweet corn, organic strawberries and blueberries, tree-ripened peaches and nectarines, sourdough breads, handmade pastries, and fresh-cut flowers.
Beyond the produce, food vendors serve gourmet crepes, handmade tamales, and other prepared foods, making it easy to spend the entire morning at the market. The combination of a race to watch, food to eat, and produce to shop creates a loop that keeps families on site for hours—the kind of multi-hour weekend outing that is increasingly rare in the age of errand-driven trips.
Market organizers frame the annual competition as much about agricultural education as entertainment. “It’s a hands-on way for kids to engage with where their food comes from,” a market spokesperson said, describing the event as “a nostalgic throwback to backyard competitions and creative play.” The requirement that zucchinis be farm-fresh rather than store-bought reinforces the connection—participants have to visit a farmers’ market or garden to source their vehicle, which means they are engaging with local agriculture before the first wheel is attached.
| Timeline | What’s Happening |
|---|---|
| 9:00 a.m. | Market opens — buy your zucchini, grab wheels and supplies, start building |
| 10:00 a.m. | Recommended latest arrival for builders — decorating supplies available at the build station |
| 10:45 a.m. | Registration closes — final call to name and enter your car |
| 11:00 a.m. | Races begin — heats, eliminations, and glory |
Strategy for First-Timers
Having covered this event, a few patterns emerge for anyone looking to bring home a $100 prize. For speed: choose a zucchini with a relatively straight, uniform shape—odd curves create drag and unpredictable trajectories on the ramp. Keep decorations minimal and low-profile; every feather and googly eye adds wind resistance. For creativity: the judges reward originality and humor over raw effort, so a clever concept executed simply will beat an elaborate build with no clear idea behind it. And for both categories: arrive by 10 a.m. at the latest. The best decorating supplies go early, and the hour between arrival and registration close disappears faster than expected when you are trying to attach wheels to produce.
If You Go
The Diablo Valley Farmers’ Market is located on Mitchell Drive in Walnut Creek. The event is free to attend and free to spectate. Participants should bring their own zucchini (purchased at the market or sourced from a local garden), arrive by 10 a.m. for adequate building and decorating time, and come prepared to name their creation—nothing is more embarrassing than making it to the final heat in a car called “Untitled Zucchini #3.”
For more information, visit CAFarmersMkts.com, follow @diablovalleyfarmersmarket on Instagram, or call 800-806-FARM. Additional details and community event listings are available through the Walnut Creek Patch community calendar.
