API & MCP

Everything a person can do on Garden Sowing Calendar (122 Plants), a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://greenplotsowingcalendar.usefulweb.site/api/v1/calculate – run Garden Sowing Calendar (122 Plants)
GET https://greenplotsowingcalendar.usefulweb.site/api/v1/tool – inputs, output schema, examples
OpenAPI 3.1: /openapi.json · /openapi.yaml
Errors: application/problem+json; 422 includes per-field errors.

Garden Sowing Calendar (122 Plants)

Turns your last spring and first autumn frost into a garden calendar for up to 60 of 122 vegetables, herbs, fruit and flowers: sow indoors, plant out, sow outside with repeat sowings, autumn planting, the harvest or flowering window, and the yearly pruning of fruit and perennials, with a calendar file.

Inputs of Garden Sowing Calendar (122 Plants)
Field	Type	Default	Description
`plants`	multiselect (tomato, pepper, eggplant, potato, cucumber, zucchini, squash, melon, sweetcorn, bush-bean, pole-bean, pea, broad-bean, lettuce, spinach, chard, beet, carrot, parsnip, radish, turnip, onio	["tomato","lettuce","strawberry","apple","sweet-pea","garlic"]	Plants
`lastFrost` (required)	text	"04-20"	Last spring frost (MM-DD). Month and day, for example 04-20. Hearth’s Frost Dates Finder gives it for Germany and the United States.
`firstFrost` (required)	text	"10-20"	First autumn frost (MM-DD)
`year`	integer	2027	Season (year of the spring frost)

Example request

Berlin: vegetables, fruit and flowers

curl -X POST https://greenplotsowingcalendar.usefulweb.site/api/v1/calculate -H 'content-type: application/json' -d '{"plants":["tomato","lettuce","strawberry","apple","sweet-pea","garlic"],"lastFrost":"04-08","firstFrost":"11-02","year":2027}'

Every result contains

inputs (normalised, defaults applied), summary, result (validated against the published schema), units, assumptions, sources, warnings, computedAt and links.

MCP (Model Context Protocol)

Streamable HTTP endpoint: https://greenplotsowingcalendar.usefulweb.site/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: greenplot_sowing_calendar
Local stdio connector: node src/mcp-stdio.ts --tool=greenplot-sowing-calendar

{
  "mcpServers": {
    "greenplot-sowing-calendar": { "type": "http", "url": "https://greenplotsowingcalendar.usefulweb.site/mcp" }
  }
}