SOURCES & DATAKnow where a result comes from.
Tiny Mustard Seed combines transparent arithmetic, maintained plant-library defaults, third-party weather data and information entered or measured by the gardener. This page separates those inputs so a result can be checked instead of treated as a black box.
Plant Library data
The Plant Library is a maintained planning dataset used to keep names and broad defaults consistent across connected tools. It includes common edible annuals, herbs, flowers, berries, perennial edibles, fruit trees and vines, plus selected regional aliases that resolve to one canonical name.
Spacing, indoor-start lead time and broad maturity values are not a substitute for cultivar, rootstock, seed-packet or nursery information. Perennial fruit trees, berries and vines are not assigned annual maturity dates simply to make them fit a calculator. Where a specific variety source is more precise, it should take priority over a broad library default.
Forecast and location data
Location lookup and short-range forecast features are implemented with Open-Meteo services. A town or postcode is resolved to coordinates, then the forecast request uses those coordinates to obtain daily minimum temperature, maximum temperature, precipitation amount and precipitation probability.
Production weather access is designed to use a commercial provider configuration rather than silently relying on a non-commercial prototype endpoint. If the production provider is not configured, weather-aware tools should fail clearly and leave manual or non-weather planning paths available.
Historical frost estimates
The frost-history workflow requests daily minimum temperatures for the previous ten complete years from the Open-Meteo historical archive using ERA5-Land data. The tool identifies threshold events within spring and autumn windows, then uses the median observed timing across available years as a planning estimate.
A historical median is not a guaranteed frost date. Local elevation, exposure, cold-air drainage, coastal influence, urban heat, shelter and unusual weather can move the practical date earlier or later than the estimate.
Crop timing defaults
The Growing Season Planner contains broad planning defaults for common crops. These defaults are used to turn frost boundaries into seed-start, direct-sow, plant-out, succession and expected-harvest targets.
They are deliberately editable. Variety-specific seed-packet guidance, reliable local extension guidance and the gardener's own records should replace a broad default when they are more specific to the crop and location.
Measured garden data
Several tools become more useful when the gardener supplies measurements. Irrigation can use a timed emitter collection test instead of the manufacturer's nominal flow, and a bucket test can estimate source-flow capacity. Harvest records use weights, counts, notes and optional values entered by the user.
Tiny Mustard Seed does not treat a user-entered measurement as independently verified. The purpose is to make the calculation reflect the real garden more closely than a generic default can.
Calculation constants
Simple garden calculations are based on visible relationships rather than proprietary scores. One millimetre of water over one square metre equals one litre. Rectangular volume is length × width × depth. Yield per square metre is recorded harvest weight divided by the saved garden area.
Rounding, whole-bag purchasing, layout losses, pressure losses and other practical allowances are described in the relevant tool or Methodology page when they can materially change the result.
Corrections and changes
Plant data, datasets, APIs and formulas can change. When a source or method changes materially, the related tool and Methodology page should be updated together so the interface does not describe a method the code no longer uses.
Weather providers do not endorse Tiny Mustard Seed merely because their data is used. Their availability, licensing and data quality remain subject to their own services and terms.