# Succession Sowing Planner

> Space repeat sowings of lettuce, radish, beans and more so you harvest all season. Plans repeat sowings of one vegetable, herb or flower from your frost dates: a sowing every few weeks, each with its harvest window and number of plants, until the last sowing that still ripens before the autumn frost — with gaps in the harvest pointed out and a timeline chart.

Part of usefulweb.site (https://usefulweb.site/). Part of [Greenplot](https://greenplot.usefulweb.site/) (ownerApp: greenplot). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://greenplotsuccessionplanner.usefulweb.site/ (interactive tool at https://greenplotsuccessionplanner.usefulweb.site/tool)
- JSON API: POST https://greenplotsuccessionplanner.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://greenplotsuccessionplanner.usefulweb.site/api/v1/tool)
- OpenAPI: https://greenplotsuccessionplanner.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://greenplotsuccessionplanner.usefulweb.site/mcp - tool `greenplot_succession_planner`

## Inputs
- plant (select): Plant
- lastFrost (text, required): 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 (text, required): First autumn frost (MM-DD)
- year (integer): Season (year of the spring frost)
- intervalWeeks (integer): Weeks between sowings (0 = the plant’s usual interval)
- squares (integer): 30 cm squares per sowing
- start (date): First sowing (optional) - Empty = start of the sowing window.

## Method
- The first sowing is the start of the plant’s outdoor sowing (or planting-out) window, counted in weeks from your last spring frost — the same window as the garden calendar — or the date you give.
- Sowings repeat every n weeks (the plant’s usual interval when you leave 0, or three weeks). The last sowing is the last one that still ripens before the end of the season: the first autumn frost minus 14 days for tender plants, the frost itself for half-hardy ones and two weeks after it for hardy ones, minus the days to harvest.
- Each sowing is picked for the interval (at least two weeks), so harvests follow on; a gap is reported where one harvest ends before the next begins. Plants per sowing = squares × plants per 30 cm square (square-foot spacing from the plant table).
- Sowings after the end of the usual sowing window are marked: many crops still ripen then, but bolting (lettuce, spinach, coriander in hot weather) and slow autumn growth are more likely.

## Limits
- Days to harvest vary with variety and weather; in midsummer choose bolt-resistant varieties and shade young sowings.