Show HN: Vertumnus – printable posters of farmers' market produce seasonality

A developer released Vertumnus, a printable poster tool showing farmers' market produce seasonality for the San Francisco and New York regions, built in a single 731-prompt Claude Opus 5 session over 22 days between July 20 and September 2, 2026. The project, posted on Hacker News, offers customizable posters per crop and publishes the full AI coding transcript and a write-up on Claude's strengths and code quality shortcomings.

The origin of this project was me, as a casual farmers' market attendee, grossly misremembering the start date of early girl tomatoes. Ironically, I still haven't achieved that goal, because I couldn't find a suitable source with varietal level granularity online. I'm half dreading a "Why didn't you check X?" comment and discover there's some perfect local varietal data source, but that would really be the best case scenario. The poster is customizable per crop, and the pictures reposition heuristically. There's only two regions, SF and NY, with very different source data for each. See https://vertumnus.fyi/about/sources https://vertumnus.fyi/about/sources for methodology. A static poster is not the greatest form factor for a schedule with annual variation, and this whole project was a non serious side exercise. See https://vertumnus.fyi/about https://vertumnus.fyi/about for more. The project was coded in a single 731 prompt Claude Opus 5 session over 22 days within a 46 day period, from July 20th to September 2nd, 2026. I've published the entire transcript, searchable and organized by chapter, at https://vertumnus.fyi/about/transcript https://vertumnus.fyi/about/transcript . A write up, with the stuff that Claude was good at and its repeated code quality shortcomings, is at https://vertumnus.fyi/about/ai https://vertumnus.fyi/about/ai . Comments URL: https://news.ycombinator.com/item?id=49604581 https://news.ycombinator.com/item?id=49604581 Points: 1 Comments: 0